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Full vulnerability report · 2026
CVE-2026-76845High confidence

adm-zip 0.5.9 through 0.6.0 Arbitrary File Overwrite via Symlink Following on Extraction

cthackers · adm-zip

6.8MediumCVSS 4.0
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Fix not verified
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-2026-76845 · CSAF 2.0 · revision 3 · finalRed Hat Product Securityadm-zip: adm-zip: Arbitrary File Overwrite via Symlink Following
32 known affected

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

  • rhacm2/volsync-operator-bundle as a component of Red Hat Advanced Cluster Management for Kubernetes 2
  • rhacm2/volsync-rhel9 as a component of Red Hat Advanced Cluster Management for Kubernetes 2
  • rh-podman-desktop.git as a component of Red Hat Build of Podman Desktop
  • rhdh/red-hat-developer-hub-backstage-plugin-lightspeed as a component of Red Hat Developer Hub
  • rhdh/red-hat-developer-hub-backstage-plugin-lightspeed-backend as a component of Red Hat Developer Hub
  • rhdh/red-hat-developer-hub-backstage-plugin-orchestrator as a component of Red Hat Developer Hub
  • rhdh/red-hat-developer-hub-backstage-plugin-orchestrator-backend as a component of Red Hat Developer Hub
  • rhdh/red-hat-developer-hub-backstage-plugin-orchestrator-backend-module-loki as a component of Red Hat Developer Hub
  • rhdh/red-hat-developer-hub-backstage-plugin-orchestrator-form-widgets as a component of Red Hat Developer Hub
  • rhdh/red-hat-developer-hub-backstage-plugin-scaffolder-backend-module-orchestrator as a component of Red Hat Developer Hub
  • rhdh/rhdh-hub-rhel9 as a component of Red Hat Developer Hub
  • mozjs60 as a component of Red Hat Enterprise Linux 8
Summary
A flaw was found in `adm-zip`, a Node.js library used for handling zip archives. This vulnerability allows a local attacker to overwrite arbitrary files on the system. When extracting an archive, `adm-zip` follows symbolic links, which are special files that point to other files or directories. An attacker can exploit this by placing a symbolic link within a temporary extraction directory, redirecting the extraction process to write data outside the intended secure location. This could lead to unauthorized modification of system files.
Remediation
Fix deferred
Optional official sources

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

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

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-2026-64851

No EUVD known-exploited evidence

adm-zip 0.5.9 through 0.6.0 follows symbolic links at the extraction destination. Utils.sanitize in util/utils.js enforces containment by comparing only the string form of an archive entry name against the resolved extraction root, and Utils.writeFileTo opens the computed destination with fs.openSync(path, "w", 0o666), which resolves symbolic links and carries neither O_NOFOLLOW nor a pre-write fs.lstatSync check. When a path component at the destination already exists as a symbolic link pointing outside the extraction root, extractAllTo, extractAllToAsync and extractEntryTo write the entry contents through that link and then chmod its target, placing attacker-controlled content in a file outside the root without any traversal sequence appearing in the archive. Reaching the write requires overwrite to be enabled, because the preceding fs.existsSync check also resolves the link and otherwise declines. An attacker able to create a symbolic link inside a shared, reused or predictable extraction directory, such as a temporary directory or a continuous integration workspace, can overwrite any file the extracting process is permitted to write.

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
6.8 · CVSS 4.0
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Fix not verified
01

What, why and how

adm-zip 0.5.9 through 0.6.0 follows symbolic links at the extraction destination. Utils.sanitize in util/utils.js enforces containment by comparing only the string form of an archive entry name against the resolved extraction root, and Utils.writeFileTo opens the computed destination with fs.openSync(path, "w", 0o666), which resolves symbolic links and carries neither O_NOFOLLOW nor a pre-write fs.lstatSync check. When a path component at the destination already exists as a symbolic link pointing outside the extraction root, extractAllTo, extractAllToAsync and extractEntryTo write the entry contents through that link and then chmod its target, placing attacker-controlled content in a file outside the root without any traversal sequence appearing in the archive. Reaching the write requires overwrite to be enabled, because the preceding fs.existsSync check also resolves the link and otherwise declines. An attacker able to create a symbolic link inside a shared, reused or predictable extraction directory, such as a temporary directory or a continuous integration workspace, can overwrite any file the extracting process is permitted to write.

What

adm-zip 0.5.9 through 0.6.0 follows symbolic links at the extraction destination. Utils.sanitize in util/utils.js enforces containment by comparing only the string form of an archive entry name against the resolved extraction root, and Utils.writeFileTo opens the computed destination with fs.openSync(path, "w", 0o666), which resolves symbolic links and carries neither O_NOFOLLOW nor a pre-write fs.lstatSync check. When a path component at the destination already exists as a symbolic link pointing outside the extraction root, extractAllTo, extractAllToAsync and extractEntryTo write the entry contents through that link and then chmod its target, placing attacker-controlled content in a file outside the root without any traversal sequence appearing in the archive. Reaching the write requires overwrite to be enabled, because the preceding fs.existsSync check also resolves the link and otherwise declines. An attacker able to create a symbolic link inside a shared, reused or predictable extraction directory, such as a temporary directory or a continuous integration workspace, can overwrite any file the extracting process is permitted to write.

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 local access may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

adm-zip 0.5.9 through 0.6.0 follows symbolic links at the extraction destination. Utils.sanitize in util/utils.js enforces containment by comparing only the string form of an archive entry name against the resolved extraction root, and Utils.writeFileTo opens the computed destination with fs.openSync(path, "w", 0o666), which resolves symbolic links and carries neither O_NOFOLLOW nor a pre-write fs.lstatSync check. When a path component at the destination already exists as a symbolic link pointing outside the extraction root, extractAllTo, extractAllToAsync and extractEntryTo write the entry contents through that link and then chmod its target, placing attacker-controlled content in a file outside the root without any traversal sequence appearing in the archive. Reaching the write requires overwrite to be enabled, because the preceding fs.existsSync check also resolves the link and otherwise declines. An attacker able to create a symbolic link inside a shared, reused or predictable extraction directory, such as a temporary directory or a continuous integration workspace, can overwrite any file the extracting process is permitted to write.

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 local access may attempt exploitation with low privileges. 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
local access → Improper Link Resolution Before File Access ('Link Following') → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Local
Privileges required
Low: a basic authenticated account is required
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:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

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

AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATNoneAttack requirements: No additional deployment or execution condition is required.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.VCNoneVulnerable-system confidentiality: No direct loss is represented by this metric.VIHighVulnerable-system integrity: A successful attack can cause a major loss.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
The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
CWE-59
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-64851Official EUVD mapping

adm-zip 0.5.9 through 0.6.0 follows symbolic links at the extraction destination. Utils.sanitize in util/utils.js enforces containment by comparing only the string form of an archive entry name against the resolved extraction root, and Utils.writeFileTo opens the computed destination with fs.openSync(path, "w", 0o666), which resolves symbolic links and carries neither O_NOFOLLOW nor a pre-write fs.lstatSync check. When a path component at the destination already exists as a symbolic link pointing outside the extraction root, extractAllTo, extractAllToAsync and extractEntryTo write the entry contents through that link and then chmod its target, placing attacker-controlled content in a file outside the root without any traversal sequence appearing in the archive. Reaching the write requires overwrite to be enabled, because the preceding fs.existsSync check also resolves the link and otherwise declines. An attacker able to create a symbolic link inside a shared, reused or predictable extraction directory, such as a temporary directory or a continuous integration workspace, can overwrite any file the extracting process is permitted to write.

Official EUVD record
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 not verified
Affected
rhacm2/volsync-operator-bundle as a component of Red Hat Advanced Cluster Management for Kubernetes 2; rhacm2/volsync-rhel9 as a component of Red Hat Advanced Cluster Management for Kubernetes 2; rh-podman-desktop.git as a component of Red Hat Build of Podman Desktop; rhdh/red-hat-developer-hub-backstage-plugin-lightspeed as a component of Red Hat Developer Hub; rhdh/red-hat-developer-hub-backstage-plugin-lightspeed-backend as a component of Red Hat Developer Hub; rhdh/red-hat-developer-hub-backstage-plugin-orchestrator as a component of Red Hat Developer Hub; rhdh/red-hat-developer-hub-backstage-plugin-orchestrator-backend as a component of Red Hat Developer Hub; rhdh/red-hat-developer-hub-backstage-plugin-orchestrator-backend-module-loki as a component of Red Hat Developer Hub; rhdh/red-hat-developer-hub-backstage-plugin-orchestrator-form-widgets as a component of Red Hat Developer Hub; rhdh/red-hat-developer-hub-backstage-plugin-scaffolder-backend-module-orchestrator as a component of Red Hat Developer Hub; rhdh/rhdh-hub-rhel9 as a component of Red Hat Developer Hub; mozjs60 as a component of Red Hat Enterprise Linux 8; mozjs60-devel as a component of Red Hat Enterprise Linux 8; mozjs60.src as a component of Red Hat Enterprise Linux 8; gjs-devel as a component of Red Hat Enterprise Linux 9; gjs.src as a component of Red Hat Enterprise Linux 9; adm-zip as a component of Red Hat Fuse 7; rhoai/odh-core-bff-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-dashboard-operator-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-dashboard-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-mlflow-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-mod-arch-agent-ops-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-mod-arch-automl-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-mod-arch-autorag-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-mod-arch-eval-hub-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-mod-arch-gen-ai-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-mod-arch-maas-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-mod-arch-mlflow-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-mod-arch-model-registry-rhel9 as a component of Red Hat OpenShift AI (RHOAI); openshift4/ose-console as a component of Red Hat OpenShift Container Platform 4; and 2 more
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 24 Aug 2026 · Last source change 24 Aug 2026, 16:25 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 2026-08-25
European sourceENISA EUVD · EUVD-2026-64851
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD received

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

Material change intelligence

What changed after publication

View recent updates →
  1. ENISA EUVD mappingEUVD-2026-64851 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-64851"}
    ENISA EUVD ↗
  2. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2026-64851↗Vendor CSAF · Red Hat Product Security↗CVE authority or vendor reference↗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-2026-76845 · cve.blacktree.nl