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Full vulnerability report · 2026
CVE-2026-4398High confidence

Authorization Bypass Through User-Controlled Key in GitLab

GitLab · GitLab

5.4MediumCVSS 3.1
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.

Patch available
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.
  • EPSS is 0.24% 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 GitLab GitLab 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.

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-2026-67167

No EUVD known-exploited evidence

GitLab has remediated an issue in GitLab EE affecting all versions from 18.3 before 19.1.7, 19.2 before 19.2.5, and 19.3 before 19.3.1 that, under certain conditions, an authenticated user could have assigned compliance frameworks from namespaces they were not authorized to access to their own project, due to missing namespace validation on self-managed instances.

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
5.4 · CVSS 3.1
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.

Patch available
01

What, why and how

GitLab has remediated an issue in GitLab EE affecting all versions from 18.3 before 19.1.7, 19.2 before 19.2.5, and 19.3 before 19.3.1 that, under certain conditions, an authenticated user could have assigned compliance frameworks from namespaces they were not authorized to access to their own project, due to missing namespace validation on self-managed instances.

What

GitLab has remediated an issue in GitLab EE affecting all versions from 18.3 before 19.1.7, 19.2 before 19.2.5, and 19.3 before 19.3.1 that, under certain conditions, an authenticated user could have assigned compliance frameworks from namespaces they were not authorized to access to their own project, due to missing namespace validation on self-managed instances.

Why

The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

GitLab has remediated an issue in GitLab EE affecting all versions from 18.3 before 19.1.7, 19.2 before 19.2.5, and 19.3 before 19.3.1 that, under certain conditions, an authenticated user could have assigned compliance frameworks from namespaces they were not authorized to access to their own project, due to missing namespace validation on self-managed instances.

Why

The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.

How

An attacker operating through a network path 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
a network path → Authorization Bypass Through User-Controlled Key → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
Low: a basic authenticated account is required
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-639 ↗

CWE-639: Authorization Bypass Through User-Controlled Key. The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.

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:L/UI:N/S:U/C:L/I:L/A:N

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.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CLowConfidentiality impact: A successful attack can cause a limited loss.ILowIntegrity impact: A successful attack can cause a limited loss.ANoneAvailability impact: 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.
NetworkCWE-639
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-67167Official EUVD mapping

GitLab has remediated an issue in GitLab EE affecting all versions from 18.3 before 19.1.7, 19.2 before 19.2.5, and 19.3 before 19.3.1 that, under certain conditions, an authenticated user could have assigned compliance frameworks from namespaces they were not authorized to access to their own project, due to missing namespace validation on self-managed instances.

Official EUVD record ↗
BSI · German · WID-SEC-2026-3029GitLab: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in GitLab ausnutzen, um beliebigen Programmcode auszuführen, um einen Denial of Service Angriff durchzuführen, um Daten zu manipulieren und um Sicherheitsvorkehrungen zu umgehen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260415Security Bulletin 15 April 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 15 April 2026, published on 15 April 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-1086Multiples vulnérabilités dans GitLab

De multiples vulnérabilités ont été découvertes dans GitLab. Certaines d'entre elles permettent à un attaquant de provoquer une exécution de code arbitraire à distance, un déni de service à distance et une atteinte à la confidentialité des données.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-035959GitLab.orgのGitLabにおけるユーザ制御の鍵による認証回避に関する脆弱性

GitLabは、GitLab EEのバージョン18.3から19.1.7未満、19.2から19.2.5未満、および19.3から19.3.1未満に影響する問題を修正しました。この問題は特定の条件下で認証済みユーザーが、自己管理インスタンスにおける名前空間の検証が欠如していたため、アクセス権限のない名前空間からコンプライアンスフレームワークを自分のプロジェクトに割り当てられる状態になっていました。

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.
Patch available
Affected
GitLab: 18.3 < 19.1.7, 19.3 < 19.3.1, 19.2 < 19.2.5
Fixed
Upgrade to versions 19.1.7, 19.2.5, 19.3.1 or above.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
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 27 Aug 2026 · Last source change 28 Aug 2026, 14:13 UTC · CWE-639 · Authorization Bypass Through User-Controlled Key

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 2026-08-28
European sourceENISA EUVD · EUVD-2026-67167
Product sourceCNA
Remediation sourceCVE/CNA references
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. BlackTree coverageBlackTree article coverage changed from no BlackTree article to 1 BlackTree article.
    Before
    no BlackTree article
    After
    1 BlackTree article
    BlackTree editorial ↗
  2. Vendor guidanceAuthoritative vendor guidance changed: added patch: docs.gitlab.com/patch-release-gitlab-19-3-1-released; added remediation: docs.gitlab.com/patch-release-gitlab-19-3-1-released.
    Before
    no authoritative guidance recorded
    After
    patch: docs.gitlab.com/patch-release-gitlab-19-3-1-released · remediation: docs.gitlab.com/patch-release-gitlab-19-3-1-released
    cve@gitlab.com ↗
  3. Affected versionsThe structured affected or fixed version information changed.
    Before
    18.3 < 19.1.7; 19.2 < 19.2.5; 19.3 < 19.3.1 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    GitLab: 18.3 < 19.1.7, 19.2 < 19.2.5, 19.3 < 19.3.1 · Fixed: Upgrade to versions 19.1.7, 19.2.5, 19.3.1 or above.
    CNA ↗
  4. Remediation statusRemediation status changed from Awaiting fix to Patch available.
    Before
    Awaiting fix
    After
    Patch available
    cve@gitlab.com ↗
  5. ENISA EUVD mappingEUVD-2026-67167 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-67167"}
    ENISA EUVD ↗
  6. Affected versionsThe structured affected or fixed version information changed.
    Before
    No structured affected-product or version range is currently available from the CVE record or NVD. · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    18.3 < 19.1.7; 19.2 < 19.2.5; 19.3 < 19.3.1 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    CNA ↗
  7. CVSS scoreCVSS scoring authority changed from Other authority to CNA; the displayed base score remained 5.4.
    Before
    5.4 (CVSS 3.1 · Other authority · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N)
    After
    5.4 (CVSS 3.1 · CNA · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N)
    CNA ↗
  8. SeveritySeverity changed from Unknown to Medium.
    Before
    Unknown
    After
    Medium
    Other authority ↗
  9. CVSS scoreCVSS score changed from not recorded to 5.4 (CVSS 3.1 · Other authority · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N).
    Before
    not recorded
    After
    5.4 (CVSS 3.1 · Other authority · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N)
    Other authority ↗
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-2026-67167↗Patch or update reference↗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-2026-4398 · cve.blacktree.nl