CVE-2023-3909: Inefficient Regular Expression Complexity in GitLab
Telemetry drift only. No threshold crossed and no authority ruling changed.
CVE record, CISA KEV and EPSS as of 2026-10-18.
CVEs like this one computed, by meaning
What to do now held facts and links
- Upgrade to the fixed version for your release line, or later: 16.3.6; 16.4.2; 16.5.1 CVE record
- Record your decision, dated and frozen with today's evidence: patch by a date · mitigated by a compensating control · deferred · accepted the risk · not affected
- Check your version against the ranges this record publishes.
What it is stated by the CNA
An issue has been discovered in GitLab CE/EE affecting all versions starting from 12.3 before 16.3.6, all versions starting from 16.4 before 16.4.2, all versions starting from 16.5 before 16.5.1. A Regular Expression Denial of Service was possible by adding a large string in timeout input in gitlab-ci.yml file.
- weakness
- CWE-1333: Inefficient Regular Expression Complexity
- affected
- GitLab
- published ranges
- gitlab >= 12.3.0 < 16.3.6; gitlab >= 16.4.0 < 16.4.2; gitlab 16.5.0
- fixed in
- 16.3.6; 16.4.2; 16.5.1
- fixed by package (from OSV advisories)
- gitlab (Bitnami): 16.3.6; 16.4.2; 16.5.1 BIT-gitlab-2023-3909
- severity
- 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
- assigned by
- GitLab
- published
- 2023-11-06
check us gitlab.com hackerone.com
Exploit code held, dated
- exploit code
- None held in the PoC-in-GitHub feed. A public repository changes this brief.
What moved held, dated
| date | EPSS | event |
|---|---|---|
| 7 Nov 2023 | 0.00043 | |
| 15 Nov 2023 | 0.00044 | |
| 6 Oct 2024 | 0.00053 | |
| 12 Nov 2024 | 0.00073 | |
| 17 Mar 2025 | 0.00774 | scoring model v2025.03.14 |
| 29 Mar 2025 | 0.00893 | |
| 30 Mar 2025 | 0.00774 | |
| 15 Apr 2025 | 0.00143 | |
| 5 Aug 2025 | 0.00023 | |
| 18 Nov 2025 | 0.00123 | |
| 21 Nov 2025 | 0.00023 | |
| 15 Jun 2026 | 0.00595 | scoring model v2026.06.15 |
| 10 Sep 2026 | 0.006 |
13 observations held. A step marked with a scoring model moved because the measurement was replaced, not because the vulnerability changed.
Outside the record researched, cited
This section reads the record's references and adds cited findings from outside it. It needs an account. Everything above is held facts and is complete without it.
What would change this brief held, dated
- CISA KEV
- Not listed in the catalogue we hold. A listing changes this brief.
- exploit probability
- 0.01 on 2026-09-10 (FIRST's EPSS, a probability and not evidence of exploitation). Next band line: 10% (0.10). Crossing a line changes this brief.
- fix
- Held: 16.3.6; 16.4.2; 16.5.1. A newer fix from the CNA or OSV changes this brief.
How to check this
Every value above is held with two dates: when it was true upstream (as_of) and when we recorded it (tx_from). Re-derive the exploit probability as it stood on any date:
SELECT value, source, source_version, as_of, tx_from
FROM volatile_valid_as_of('CVE-2023-3909', '2026-11-01T23:59:59.999999Z', now());