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Full vulnerability report · 2026
CVE-2026-23831High confidence

Rekor COSE v0.0.1 Canonicalize crashes when passed empty Message

sigstore · rekor

Official source article: GitHub GHSA-273P-M2CW-6833 ↗. Check the applicable product and release in the original source.

5.3MediumCVSS 3.1
Recommended action
Patch only the product branches with a verified fix

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. 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 severityMediumOperational priority:Medium, 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 0.43% 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 sigstore rekor 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: As exposure requiresRemediation target: Within 365 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 findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

3 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 · sourcerekorAffected, no fix publishedDebian currently tracks this release as open.Not published in this feedDebian Security Tracker ↗Source updated 6 Oct 2026
Debian forkyforky · sourcerekorVendor fix publishedDebian records a fixed source-package version for this release.1.5.0-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian sidsid · sourcerekorVendor fix publishedDebian records a fixed source-package version for this release.1.5.0-1Debian Security Tracker ↗Source updated 6 Oct 2026
Open-source package ranges2 source-attributed ranges

These OSV and GitHub advisory ranges apply only to the named package and ecosystem. A listed fixed version is not a universal product patch or proof that an update is installed.

Ecosystem and packageAffected rangeFirst fixed versionEvidence
Gogithub.com/sigstore/rekorSEMVER: introduced 0; fixed 1.5.01.5.0OSV record ↗aggregator derived · 10 Sep 2026
gogithub.com/sigstore/rekor<= 1.4.31.5.0GitHub advisory ↗upstream repository advisory · 23 Jan 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.

2 current
CVE-2026-23831 · CSAF 2.0 · revision 11 · interimSUSE Product Security TeamCVE-2026-23831
22 known affected

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

  • rekor as component of SUSE Linux Enterprise Desktop 15 SP7
  • rekor as component of SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS
  • rekor as component of SUSE Linux Enterprise High Performance Computing 15 SP4
  • rekor as component of SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS
  • rekor as component of SUSE Linux Enterprise High Performance Computing 15 SP5
  • rekor as component of SUSE Linux Enterprise Module for Basesystem 15 SP7
  • rekor as component of SUSE Linux Enterprise Server 15 SP4-LTSS
  • rekor as component of SUSE Linux Enterprise Server 15 SP4
  • rekor as component of SUSE Linux Enterprise Server 15 SP5-LTSS
  • rekor as component of SUSE Linux Enterprise Server 15 SP5
  • rekor as component of SUSE Linux Enterprise Server 15 SP6-LTSS
  • rekor as component of SUSE Linux Enterprise Server 15 SP6
Summary
Rekor is a software supply chain transparency log. In versions 1.4.3 and below, the entry implementation can panic on attacker-controlled input when canonicalizing a proposed entry with an empty spec.message, causing nil Pointer Dereference. Function validate() returns nil (success) when message is empty, leaving sign1Msg uninitialized, and Canonicalize() later dereferences v.sign1Msg.Payload. A malformed proposed entry of the cose/v0.0.1 type can cause a panic on a thread within the Rekor process. The thread is recovered so the client receives a 500 error message and service still continues, so the availability impact of this is minimal. This issue has been fixed in version 1.5.0.
Remediation
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
CVE-2026-23831 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitygithub.com/sigstore/rekor: Rekor denial of service
185 known affected

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

  • assisted/agent-preinstall-image-builder-rhel9 as a component of Assisted Installer for Red Hat OpenShift Container Platform 2
  • rhai/assisted-installer-controller-rhel9 as a component of Assisted Installer for Red Hat OpenShift Container Platform 2
  • compliance/openshift-compliance-must-gather-rhel8 as a component of Compliance Operator
  • openshift-sandboxed-containers/osc-must-gather-rhel9 as a component of Confidential Compute Attestation
  • openshift-sandboxed-containers/osc-podvm-builder-rhel9 as a component of Confidential Compute Attestation
  • compliance/openshift-compliance-must-gather-rhel8 as a component of File Integrity Operator
  • kmm/kernel-module-management-must-gather-rhel9 as a component of Kernel Module Management Operator for Red Hat Openshift
  • openshift-logging/cluster-logging-rhel9-operator as a component of Logging Subsystem for Red Hat OpenShift
  • lvms4/lvms-must-gather-rhel9 as a component of Logical Volume Manager Storage
  • rhmtc/openshift-migration-controller-rhel8 as a component of Migration Toolkit for Containers
  • rhmtc/openshift-migration-log-reader-rhel8 as a component of Migration Toolkit for Containers
  • rhmtc/openshift-migration-must-gather-rhel8 as a component of Migration Toolkit for Containers
Summary
Rekor’s cose v0.0.1 entry implementation can panic on attacker-controlled input when canonicalizing a proposed entry with an empty spec.message. validate() returns nil (success) when message is empty, leaving sign1Msg uninitialized, and Canonicalize() later dereferences v.sign1Msg.Payload. A malformed proposed entry of the cose/v0.0.1 type can cause a panic on a thread within the Rekor process. The thread is recovered so the client receives a 500 error message and service still continues, so the availability impact of this is minimal.
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://docs.redhat.com/en/documentation/red_hat_openshift_data_foundation/4.22/html/updating_openshift_data_foundation/updating-ocs-to-odf_rhodf
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-2026-3809

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

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
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionPatch only the product branches with a verified fix

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

Rekor is a software supply chain transparency log. In versions 1.4.3 and below, the entry implementation can panic on attacker-controlled input when canonicalizing a proposed entry with an empty spec.message, causing nil Pointer Dereference. Function validate() returns nil (success) when message is empty, leaving sign1Msg uninitialized, and Canonicalize() later dereferences v.sign1Msg.Payload. A malformed proposed entry of the cose/v0.0.1 type can cause a panic on a thread within the Rekor process. The thread is recovered so the client receives a 500 error message and service still continues, so the availability impact of this is minimal. This issue has been fixed in version 1.5.0.

What

Rekor is a software supply chain transparency log. In versions 1.4.3 and below, the entry implementation can panic on attacker-controlled input when canonicalizing a proposed entry with an empty spec.message, causing nil Pointer Dereference. Function validate() returns nil (success) when message is empty, leaving sign1Msg uninitialized, and Canonicalize() later dereferences v.sign1Msg.Payload. A malformed proposed entry of the cose/v0.0.1 type can cause a panic on a thread within the Rekor process. The thread is recovered so the client receives a 500 error message and service still continues, so the availability impact of this is minimal. This issue has been fixed in version 1.5.0.

Why

The product dereferences a pointer that it expects to be valid but is NULL.

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

Rekor is a software supply chain transparency log. In versions 1.4.3 and below, the entry implementation can panic on attacker-controlled input when canonicalizing a proposed entry with an empty spec.message, causing nil Pointer Dereference. Function validate() returns nil (success) when message is empty, leaving sign1Msg uninitialized, and Canonicalize() later dereferences v.sign1Msg.Payload. A malformed proposed entry of the cose/v0.0.1 type can cause a panic on a thread within the Rekor process. The thread is recovered so the client receives a 500 error message and service still continues, so the availability impact of this is minimal. This issue has been fixed in version 1.5.0.

Why

The product dereferences a pointer that it expects to be valid but is NULL.

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 → NULL Pointer Dereference → 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
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-476 ↗

CWE-476: NULL Pointer Dereference. The product dereferences a pointer that it expects to be valid but is NULL.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Common Vulnerability Scoring System 3.1: 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.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.ALowAvailability impact: A successful attack can cause a limited loss.
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-476
A

Official authority intelligence

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

Cyber Security Agency of Singapore · English · CSA-SB-20260128Security Bulletin 28 Jan 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 28 Jan 2026, published on 28 January 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0315Multiples vulnérabilités dans les produits VMware

ord?id=CVE-2026-21932 Référence CVE CVE-2026-21933 https://www.cve.org/CVERecord?id=CVE-2026-21933 Référence CVE CVE-2026-21945 https://www.cve.org/CVERecord?id=CVE-2026-21945 Référence CVE CVE-2026-22701 https://www.cve.org/CVERecord?id=CVE-2026-22701 Référence CVE CVE-2026-22702 https://www.cve.org/CVERecord?id=CVE-2026-22702 Référence CVE CVE-2026-22703 https://www.cve.org/CVERecord?id=CVE-2026-22703 Référence CVE CVE-2026-22795 https://www.cve.org/CVERecord?id=CVE-2026-22795 Référence CVE CVE-2026-22796 https://www.cve.org/CVERecord?id=CVE-2026-22796 Référence CVE CVE-2026-2297 https://www.cve.org/CVERecord?id=CVE-2026-2297 Référence CVE CVE-2026-23831 https://www.cve.org/CVERecord?id=CVE-2026-23831 Référence CVE CVE-2026-24117 https://www.cve.org/CVERecord?id=CVE-2026-24117 Référence CVE CVE-2026-24137 https://www.cve.org/CVERecord?id=CVE-2026-24137 Référence CVE CVE-2026-24733 https://www.cve.org/CVERecord?id=CVE-2026-24733 Référence CVE CVE-2026-25679 https://www.cve.org/CVERecord?id=CVE-2026-25679 Référence CVE CVE-2026-25934 https://www.cve.org/CVERecord?id=CVE-2026-25934 Référence CVE CVE-2026-26958 https://www.cve.org/CVERecord?id=CVE-2026-26958 Référence CVE CVE-2026-27137 https://www.cve.org/CVERecord?id=CVE-2026-27137 Référence CVE CVE-2026-27138 https://www.cve.org/CVERecord?id=

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-002524Linux FoundationのrekorにおけるNULL ポインタデリファレンスに関する脆弱性

Rekorはソフトウェアサプライチェーンの透明性ログを提供するシステムです。バージョン1.4.3以下では、entryの実装が空のspec.messageを持つ提案されたエントリを正規化する際に、攻撃者が制御する入力によりパニックを引き起こし、nilポインタ参照が発生する可能性があります。関数validate()はmessageが空の場合にnil（成功）を返し、その結果sign1Msgが初期化されず、続いてCanonicalize()がv.sign1Msg.Payloadをデリファレンスします。cose/v0.0.1タイプの不正な提案エントリによってRekorプロセス内のスレッドでパニックが引き起こされます。スレッドは回復されるため、クライアントは500エラーメッセージを受け取りサービスは継続されるため、可用性への影響が最小限に抑えられます。この問題はバージョン1.5.0で修正されています。

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
1.5.0.
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.
04

Evidence and provenance

Published 22 Jan 2026 · Last source change 23 Jan 2026, 14:32 UTC · CWE-476 · NULL Pointer Dereference

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 2026-08-14
European sourceENISA EUVD · EUVD-2026-3809
Product sourceVendor CSAF · SUSE Product Security Team
Remediation sourceVendor CSAF · SUSE Product Security Team
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 ↗

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

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-2026-3809↗Vendor CSAF · SUSE Product Security Team↗CVE authority or vendor reference · GitHub GHSA-273P-M2CW-6833↗Patch or update 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-2026-23831 · cve.blacktree.nl