CVE-2021-39935
SSRF in Gitlab 10.5.0 – 14.3.6
Raw vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:NSummary
CVE-2021-39935 is a medium-severity SSRF (CWE-918) vulnerability in Gitlab Gitlab. Its CVSS base score is 6.8 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 2% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2021-39935 is a server-side request forgery vulnerability tracked under CWE-918 that affects the CI Lint API in GitLab Community Edition and Enterprise Edition. The flaw impacts all versions from 10.5 up to but not including 14.3.6, all versions from 14.4 up to but not including 14.4.4, and all versions from 14.5 up to but not including 14.5.2. It carries a CVSS 3.1 score of 6.8 with the vector AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N.
Unauthorized external users can exploit the issue by submitting crafted requests to the CI Lint API, enabling them to initiate server-side requests to arbitrary internal or external resources. This allows potential access to sensitive data or internal services that would otherwise be unreachable from outside the network.
Public advisories and the associated GitLab issue direct users to upgrade to the fixed releases 14.3.6, 14.4.4, or 14.5.2 (or later) to remediate the vulnerability. No additional configuration changes or workarounds are specified in the provided references.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-26291
Vulnerability Data
An issue has been discovered in GitLab CE/EE affecting all versions starting from 10.5 before 14.3.6, all versions starting from 14.4 before 14.4.4, all versions starting from 14.5 before 14.5.2. Unauthorized external users could perform Server Side Requests via the…
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CI Lint API
- CWE(s)
- KEV Date Added
- 03 February 2026
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V1.3.6V1.5.3V5.3.2V10.4.7
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Penetration testing attempts server-side requests to internal resources, identifying SSRF weaknesses for remediation.
Outbound connections to external resources can be monitored and limited at the boundary, reducing SSRF impact.
Validates server-side URLs and resource references to block SSRF attempts.
Detects server-side request forgery through monitoring of unexpected outbound connections.
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.
Secure development practices directly include input validation and destination allow-listing that prevent SSRF.
Runtime monitoring of web applications and services can detect anomalous outbound requests indicative of SSRF.
Vulnerability identification processes can discover and record SSRF flaws in web applications.
Network segmentation and egress controls can limit the damage from successful SSRF requests.
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.
Operational threat data describing SSRF campaigns can be used to tighten outbound-request allow-lists and detection rules before attackers exploit them.