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:NCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
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 16th 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 IA-3 (Device Identification and Authentication) and SC-20 (Secure Name/Address Resolution Service (Authoritative Source)) — 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 Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Requiring unique device identification and authentication before any connection prevents security decisions based solely on unverified reverse DNS lookups.
Mandating data-origin authentication for name/address resolution stops reliance on unauthenticated reverse DNS responses.
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.