CVE-2026-12635
Gitlab 8.3.0 – 18.11.6
Raw vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:NSummary
CVE-2026-12635 is a uncategorised-severity Reliance on Reverse DNS Resolution for a Security-Critical Action (CWE-350) vulnerability in Gitlab Gitlab. Its CVSS base score is 0.0.
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 6th 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 AC-4 (Information Flow Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-39168
Vulnerability Data
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 8.3 before 18.11.6, 19.0 before 19.0.3, and 19.1 before 19.1.1 that under certain conditions could have allowed an authenticated user with maintainer-role permissions to make requests to internal…
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network resources through mirror synchronization due to improper URL validation.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
SSRF via improper URL validation in public-facing GitLab app directly enables T1190.
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
Mitigating Controls (NIST 800-53 r5) AI
Directly requires validation of URLs supplied for mirror synchronization to block malformed or internal-target addresses.
Enforces information-flow policy that denies requests from the GitLab instance to internal network resources via the mirror feature.
Boundary-protection mechanisms can be configured to inspect and drop outbound synchronization traffic destined for internal address space.
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.
Strong authentication of users/services/hardware directly prevents security decisions based on unauthenticated reverse DNS.
Monitoring DNS services can detect adverse events stemming from unverified reverse lookups.
Network protections reduce the feasibility of attackers exploiting unauthenticated reverse-DNS decisions.
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.
Network security controls can enforce authenticated, non-DNS-based host identification.
Secure network services discourage use of unauthenticated reverse-DNS for access decisions.
Application security requirements can mandate authenticated host verification instead of reverse DNS.
Secure architecture principles discourage reliance on unauthenticated DNS for security decisions.
Secure coding practices can replace reverse-DNS checks with cryptographically verified identities.
Strong authentication mechanisms reduce reliance on unauthenticated DNS-based identity decisions.