Cyber Resilience

CVE-2025-8405

Gitlab 17.1.0 – 18.4.6

Published
11 December 2025
Modified
23 December 2025
Patch / advisory
View advisory
CVSS Score v3.1 7.7
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N
EPSS Score 0.0049 40th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2025-8405 is a high-severity Improper Encoding or Escaping of Output (CWE-116) vulnerability in Gitlab Gitlab. Its CVSS base score is 7.7 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Content Injection (T1659); ranked at the 40th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and SI-15 (Information Output Filtering) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A05:2025 Injection

EU & UK References

Vulnerability Data

GitLab has remediated a security issue in GitLab CE/EE affecting all versions from 17.1 before 18.4.6, 18.5 before 18.5.4, and 18.6 before 18.6.2 that could have allowed an authenticated user to perform unauthorized actions on behalf of other users by…

more

injecting malicious HTML into vulnerability code flow displays.

CWE(s)
CWE-116

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1659 Content Injection Initial Access
Adversaries may gain access and continuously communicate with victims by injecting malicious content into systems through online network traffic.
attack.mitre.org →
Why these techniques?

Explicit malicious HTML injection into app displays enabling unauthorized actions matches T1659 directly.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2024-6329Same product: Gitlab Gitlab
CVE-2025-12697Same product: Gitlab Gitlab
CVE-2025-12734Same product: Gitlab Gitlab
CVE-2026-9694Same product: Gitlab Gitlab
CVE-2023-2200Same product: Gitlab Gitlab
CVE-2024-4099Same product: Gitlab Gitlab
CVE-2023-2030Same product: Gitlab Gitlab
CVE-2026-13151Same product: Gitlab Gitlab
CVE-2024-1211Same product: Gitlab Gitlab
CVE-2023-5009Same product: Gitlab Gitlab

Affected Assets

gitlab
gitlab
17.1.0 — 18.4.6 · 17.1.0 — 18.4.6 · 18.5.0 — 18.5.4

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SI-10 Information Input Validation
  • SI-15 Information Output Filtering
  • AC-4 Information Flow Enforcement
Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V1.1.2
  • V1.2.1
  • V1.2.3

Mitigating Controls (NIST 800-53 r5) AI

SI-10 Information Input Validation good match
prevent

Directly requires validation and sanitization of inputs/outputs to block malicious HTML injection into vulnerability displays.

SI-15 Information Output Filtering good match
prevent

Enforces output filtering to prevent display of untrusted or malicious HTML that could trigger unauthorized actions.

AC-4 Information Flow Enforcement partial match
prevent

Controls information flows between system components to stop injected content from affecting other users' sessions or actions.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require proper output encoding to prevent injection and message malformation.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.28 Secure coding mostly match
prevents

Secure coding standards explicitly require correct output encoding and escaping to preserve message structure.

A.8.29 Security testing in development and acceptance mostly match
detects

Security testing can detect missing or incorrect encoding but does not itself implement the control.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle mandates output encoding/escaping practices that directly prevent improper encoding.

A.8.26 Application security requirements partial match
prevents

Application security requirements include explicit rules for safe output handling and encoding.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles reduce the likelihood of missing encoding but do not prescribe the actual technique.

References