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Full vulnerability report · 2026
CVE-2026-100690High confidence

Hugo v0.161.0 to v0.165.0 Arbitrary File Read via Symlinks

gohugoio · hugo

Official source article: GitHub GHSA-X3MX-CM49-8M9C ↗. Check the applicable product and release in the original source.

8.7HighCVSS 4.0
Recommended action
Patch only the product branches with a verified fix

High technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:High, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 0.35% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs gohugoio hugo and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 30 daysRemediation target: Within 180 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Cross-source reconciliation

Remediation availability differs by product scope

Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Distribution package intelligence

Release-specific package status

Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

5 package states
Package result overrides the generic status

BlackTree has verified remediation for at least one product or source, but the relevant distribution still reports no fixed package for 1 affected package state shown here. Treat those rows as affected with no fix until that distribution publishes a fixed version.

Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Distribution releaseSource packageVendor stateFixed versionEvidence
Debian trixietrixie · sourcehugoNot affectedDebian marks this release not affected (fixed-version marker 0).Not published in this feedDebian Security Tracker ↗Source updated 8 Oct 2026
Debian bookwormbookworm · sourcehugoNot affectedDebian marks this release not affected (fixed-version marker 0).Not published in this feedDebian Security Tracker ↗Source updated 8 Oct 2026
Debian forkyforky · sourcehugoAffected, no fix publishedDebian currently tracks this release as open.Not published in this feedDebian Security Tracker ↗Source updated 8 Oct 2026
Debian sidsid · sourcehugoVendor fix publishedDebian records a fixed source-package version for this release.0.166.0-1Debian Security Tracker ↗Source updated 8 Oct 2026
Ubuntu 24.04 LTSnoble · esm-appshugoUnder evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical Ubuntu Security ↗Source updated 8 Oct 2026
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
CVE-2026-100690 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitygithub.com/gohugoio/hugo: Hugo: Arbitrary file read via symbolic link sandbox escape
2 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • openshift-gitops-1/argocd-rhel8 as a component of Red Hat OpenShift GitOps
  • openshift-gitops-1/argocd-rhel9 as a component of Red Hat OpenShift GitOps
Summary
A flaw was found in Hugo. This vulnerability allows information disclosure when Hugo executes build tools under the Node.js permission model, which validates only lexical file paths and fails to restrict symbolic links pointing outside the sandbox. An attacker capable of contributing content to a repository can exploit this by committing a symbolic link targeting sensitive host files alongside a build tool that reads it. Consequently, files readable by the build process can be exposed and embedded into the published site.
Remediation
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-87663

No EUVD known-exploited evidence

Hugo versions from v0.161.0 through v0.165.0 run Node.js tools (css.PostCSS, css.TailwindCSS, js.Babel) under the Node.js permission model to restrict file system reads to the project directory and configured mounts. Because the Node.js permission model validates only the lexical path and follows symbolic links that point outside the allowed set, Hugo did not detect symlinks escaping the sandbox. An attacker who can contribute content to a Hugo project (for example via a pull request) can commit a symlink such as assets/css/x.css -> /etc/passwd together with a PostCSS plugin that reads it, allowing any file readable by the Hugo build process to be disclosed and potentially embedded in the published site. This affects builds using the default security configuration; projects that do not invoke Node.js tools are unaffected. Fixed in v0.166.0, which scans allowed paths and fails the build when a symbolic link resolves outside them.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
8.7 · CVSS 4.0
Advisory evidence
No linked advisory details stored yet
Recommended actionPatch only the product branches with a verified fix

High technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
01

What, why and how

Hugo versions from v0.161.0 through v0.165.0 run Node.js tools (css.PostCSS, css.TailwindCSS, js.Babel) under the Node.js permission model to restrict file system reads to the project directory and configured mounts. Because the Node.js permission model validates only the lexical path and follows symbolic links that point outside the allowed set, Hugo did not detect symlinks escaping the sandbox. An attacker who can contribute content to a Hugo project (for example via a pull request) can commit a symlink such as assets/css/x.css -> /etc/passwd together with a PostCSS plugin that reads it, allowing any file readable by the Hugo build process to be disclosed and potentially embedded in the published site. This affects builds using the default security configuration; projects that do not invoke Node.js tools are unaffected. Fixed in v0.166.0, which scans allowed paths and fails the build when a symbolic link resolves outside them.

What

Hugo versions from v0.161.0 through v0.165.0 run Node.js tools (css.PostCSS, css.TailwindCSS, js.Babel) under the Node.js permission model to restrict file system reads to the project directory and configured mounts. Because the Node.js permission model validates only the lexical path and follows symbolic links that point outside the allowed set, Hugo did not detect symlinks escaping the sandbox. An attacker who can contribute content to a Hugo project (for example via a pull request) can commit a symlink such as assets/css/x.css -> /etc/passwd together with a PostCSS plugin that reads it, allowing any file readable by the Hugo build process to be disclosed and potentially embedded in the published site. This affects builds using the default security configuration; projects that do not invoke Node.js tools are unaffected. Fixed in v0.166.0, which scans allowed paths and fails the build when a symbolic link resolves outside them.

Why

The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Hugo versions from v0.161.0 through v0.165.0 run Node.js tools (css.PostCSS, css.TailwindCSS, js.Babel) under the Node.js permission model to restrict file system reads to the project directory and configured mounts. Because the Node.js permission model validates only the lexical path and follows symbolic links that point outside the allowed set, Hugo did not detect symlinks escaping the sandbox. An attacker who can contribute content to a Hugo project (for example via a pull request) can commit a symlink such as assets/css/x.css -> /etc/passwd together with a PostCSS plugin that reads it, allowing any file readable by the Hugo build process to be disclosed and potentially embedded in the published site. This affects builds using the default security configuration; projects that do not invoke Node.js tools are unaffected. Fixed in v0.166.0, which scans allowed paths and fails the build when a symbolic link resolves outside them.

Why

The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Improper Link Resolution Before File Access ('Link Following') → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-59 ↗

CWE-59: Improper Link Resolution Before File Access ('Link Following'). The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.VCHighVulnerable-system confidentiality: A successful attack can cause a major loss.VINoneVulnerable-system integrity: No direct loss is represented by this metric.VANoneVulnerable-system availability: No direct loss is represented by this metric.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-59
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-87663Official EUVD mapping

Hugo versions from v0.161.0 through v0.165.0 run Node.js tools (css.PostCSS, css.TailwindCSS, js.Babel) under the Node.js permission model to restrict file system reads to the project directory and configured mounts. Because the Node.js permission model validates only the lexical path and follows symbolic links that point outside the allowed set, Hugo did not detect symlinks escaping the sandbox. An attacker who can contribute content to a Hugo project (for example via a pull request) can commit a symlink such as assets/css/x.css -> /etc/passwd together with a PostCSS plugin that reads it, allowing any file readable by the Hugo build process to be disclosed and potentially embedded in the published site. This affects builds using the default security configuration; projects that do not invoke Node.js tools are unaffected. Fixed in v0.166.0, which scans allowed paths and fails the build when a symbolic link resolves outside them.

Official EUVD record ↗
JVN iPedia · Japanese · JVNDB-2026-036142GoHugoのHugoにおけるリンク解釈に関する脆弱性

Hugoのv0.161.0からv0.165.0までのバージョンは、Node.jsの許可モデルの下でNode.jsツール（css.PostCSS、css.TailwindCSS、js.Babel）を実行し、ファイルシステムの読み取りをプロジェクトディレクトリおよび設定されたマウントに制限しています。しかし、Node.jsの許可モデルは字句的なパスのみを検証し、許可された範囲外を指すシンボリックリンクをたどることがあるため、Hugoはサンドボックスを脱出するシンボリックリンクを検出できませんでした。Hugoプロジェクトにコンテンツを提供できる攻撃者（例えばプルリクエストを介して）は、assets/css/x.cssが/etc/passwdを指すようなシンボリックリンクを、このリンクを読み取るPostCSSプラグインと共にコミットできます。その結果、Hugoビルドプロセスが読み取れる任意のファイルが漏洩し、公開サイトに埋め込まれる可能性があります。この問題はデフォルトのセキュリティ設定を使用したビルドに影響し、Node.jsツールを呼び出さないプロジェクトには影響しません。v0.166.0で修正されており、許可されたパスをスキャンしてシンボリックリンクがその範囲外に解決される場合はビルドを失敗させるように変更されました。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix availability varies by product
Affected
Fixed
Action
Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
Official vendor articles1 stored document

Linked articles are downloaded and versioned as source evidence. A CVE mention or approved update relationship does not, by itself, verify a fix for every product branch.

04

Evidence and provenance

Published 26 Sept 2026 · Last source change 30 Sept 2026, 15:04 UTC · CWE-59 · Improper Link Resolution Before File Access ('Link Following')

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-09-27
European sourceENISA EUVD · EUVD-2026-87663
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Vendor guidanceAuthoritative vendor guidance changed from remediation: access.redhat.com/CVE-2026-100690 to remediation: access.redhat.com/CVE-2026-100690.
    Before
    remediation: access.redhat.com/CVE-2026-100690
    After
    remediation: access.redhat.com/CVE-2026-100690
    Red Hat Product Security ↗
  2. Affected versionsThe structured affected or fixed version information changed.
    Before
    openshift-gitops-1/argocd-rhel8 as a component of Red Hat OpenShift GitOps; openshift-gitops-1/argocd-rhel9 as a component of Red Hat OpenShift GitOps · Fixed: hugo-0:0.166.0-0.1.hum1@aarch64 as a component of Red Hat Hardened Images; hugo-0:0.166.0-0.1.hum1@src as a component of Red Hat Hardened Images; hugo-0:0.166.0-0.1.hum1@x86_64 as a component of Red Hat Hardened Images
    After
    openshift-gitops-1/argocd-rhel8 as a component of Red Hat OpenShift GitOps; openshift-gitops-1/argocd-rhel9 as a component of Red Hat OpenShift GitOps · Fixed: registry.redhat.io/cluster-observability-operator/korrel8r-rhel9@sha256:134bae4b372afbb36cc1c95c549f9c5b913e7937f244420c82dbb24788d0b1c2_s390x as a component of Cluster Observability Operator 1.5.3; registry.redhat.io/cluster-observability-operator/korrel8r-rhel9@sha256:1ce7459d152ee210ae9f0a5a082f0717367b67eda6ae0f82de432128ee99a336_ppc64le as a component of Cluster Observability Operator 1.5.3; registry.redhat.io/cluster-observability-operator/korrel8r-rhel9@sha256:349a98ad8537c8bc08f67ebd30d7b407b654779b233a6eb69d42ba9b195141bd_amd64 as a component of Cluster Observability Operator 1.5.3; registry.redhat.io/cluster-observability-operator/korrel8r-rhel9@sha256:53f5d6886f01197c1d9e7f979ba5d1b634a25eb3cbf0a579197a1ab64e26f311_arm64 as a component of Cluster Observability Operator 1.5.3; hugo-0:0.166.0-0.1.hum1@aarch64 as a component of Red Hat Hardened Images; hugo-0:0.166.0-0.1.hum1@src as a component of Red Hat Hardened Images; hugo-0:0.166.0-0.1.hum1@x86_64 as a component of Red Hat Hardened Images
    Red Hat Product Security ↗
  3. Affected versionsThe structured affected or fixed version information changed.
    Before
    grafana12.4.src as a component of Red Hat Hardened Images; grafana13.1.src as a component of Red Hat Hardened Images; grafana13.2.src as a component of Red Hat Hardened Images; openshift-gitops-1/argocd-rhel8 as a component of Red Hat OpenShift GitOps; openshift-gitops-1/argocd-rhel9 as a component of Red Hat OpenShift GitOps · Fixed: hugo-0:0.166.0-0.1.hum1@aarch64 as a component of Red Hat Hardened Images; hugo-0:0.166.0-0.1.hum1@src as a component of Red Hat Hardened Images; hugo-0:0.166.0-0.1.hum1@x86_64 as a component of Red Hat Hardened Images
    After
    openshift-gitops-1/argocd-rhel8 as a component of Red Hat OpenShift GitOps; openshift-gitops-1/argocd-rhel9 as a component of Red Hat OpenShift GitOps · Fixed: hugo-0:0.166.0-0.1.hum1@aarch64 as a component of Red Hat Hardened Images; hugo-0:0.166.0-0.1.hum1@src as a component of Red Hat Hardened Images; hugo-0:0.166.0-0.1.hum1@x86_64 as a component of Red Hat Hardened Images
    Red Hat Product Security ↗
  4. Vendor guidanceAuthoritative vendor guidance changed from remediation: access.redhat.com/CVE-2026-100690 to remediation: access.redhat.com/CVE-2026-100690.
    Before
    remediation: access.redhat.com/CVE-2026-100690
    After
    remediation: access.redhat.com/CVE-2026-100690
    Red Hat Product Security ↗
  5. Remediation statusRemediation status changed from Mitigation available to Patch available.
    Before
    Mitigation available
    After
    Patch available
    Red Hat Product Security ↗
  6. Affected versionsThe structured affected or fixed version information changed.
    Before
    grafana as a component of Red Hat Enterprise Linux 10; grafana-selinux as a component of Red Hat Enterprise Linux 10; grafana.src as a component of Red Hat Enterprise Linux 10; grafana12.4.src as a component of Red Hat Hardened Images; grafana13.1.src as a component of Red Hat Hardened Images; grafana13.2.src as a component of Red Hat Hardened Images; hugo.src as a component of Red Hat Hardened Images; openshift-gitops-1/argocd-rhel8 as a component of Red Hat OpenShift GitOps; openshift-gitops-1/argocd-rhel9 as a component of Red Hat OpenShift GitOps; rhoso-operators/openstack-operator-bundle as a component of Red Hat OpenStack Platform 18.0
    After
    grafana12.4.src as a component of Red Hat Hardened Images; grafana13.1.src as a component of Red Hat Hardened Images; grafana13.2.src as a component of Red Hat Hardened Images; openshift-gitops-1/argocd-rhel8 as a component of Red Hat OpenShift GitOps; openshift-gitops-1/argocd-rhel9 as a component of Red Hat OpenShift GitOps · Fixed: hugo-0:0.166.0-0.1.hum1@aarch64 as a component of Red Hat Hardened Images; hugo-0:0.166.0-0.1.hum1@src as a component of Red Hat Hardened Images; hugo-0:0.166.0-0.1.hum1@x86_64 as a component of Red Hat Hardened Images
    Red Hat Product Security ↗
  7. ENISA EUVD mappingEUVD-2026-87663 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-87663"}
    ENISA EUVD ↗
  8. Vendor guidanceAuthoritative vendor guidance changed: added vendor advisory: github.com/GHSA-x3mx-cm49-8m9c.
    Before
    remediation: github.com/GHSA-x3mx-cm49-8m9c
    After
    remediation: github.com/GHSA-x3mx-cm49-8m9c · vendor advisory: github.com/GHSA-x3mx-cm49-8m9c
    disclosure@vulncheck.com ↗
  9. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2026-87663↗Vendor CSAF · Red Hat Product Security↗CVE authority or vendor reference · GitHub GHSA-X3MX-CM49-8M9C↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-100690 · cve.blacktree.nl