CVE-2026-1388
Gitlab 9.2.0 – 18.7.5
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-1388 is a high-severity Inefficient Regular Expression Complexity (CWE-1333) vulnerability in Gitlab Gitlab. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked at the 34th 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 SA-11 (Developer Testing and Evaluation) and SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.
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-2026-1388 is a regular expression denial of service (ReDoS) vulnerability, classified under CWE-1333, affecting GitLab Community Edition (CE) and Enterprise Edition (EE) in all versions from 9.2 prior to 18.7.5, 18.8 prior to 18.8.5, and 18.9 prior to 18.9.1. The issue resides in a merge request endpoint, where specially crafted input can trigger excessive resource consumption due to inefficient regular expression processing.
An unauthenticated attacker can exploit this vulnerability over the network with low complexity and no privileges by submitting malicious input to the affected merge request endpoint under certain conditions. Successful exploitation results in a denial of service, disrupting service availability with a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H), potentially causing significant resource exhaustion on the GitLab server.
GitLab has remediated the vulnerability through patch releases, including GitLab 18.9.1, with corresponding fixes in 18.7.5 and 18.8.5. Security practitioners should upgrade to these patched versions immediately, as detailed in the official release notes, the associated GitLab issue tracker entry, and the HackerOne disclosure report.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-8721
Vulnerability Data
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 9.2 before 18.7.5, 18.8 before 18.8.5, and 18.9 before 18.9.1 that could have allowed an unauthenticated user to cause regular expression denial of service by sending specially crafted…
more
input to a merge request endpoint under certain conditions.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover inefficient regex patterns via performance or static analysis.
Development standards and tools can require safe regex construction and forbid known exponential patterns.
Denial-of-service protections limit resource exhaustion caused by expensive regex evaluation.
Input validation can constrain data that would otherwise trigger worst-case regex complexity.
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.
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.
Security testing can detect and reject regex patterns with exponential worst-case complexity.
Secure coding standards explicitly prohibit or limit the use of inefficient regular expressions.