CVE-2026-16255
MEDIUMDescription
GitLab has remediated an issue in GitLab EE affecting all versions from 12.0 before 19.3.6, 19.4 before 19.4.3, and 19.5 before 19.5.1 that, when the instance-wide SAML or LDAP membership lock was enabled, an authenticated user could have granted or accepted project and group membership outside the identity provider's control, due to incomplete enforcement of the membership lock on requests created before the lock was enabled.
How to fix
No published remediation has been found for this vulnerability's affected products yet.
Mitigation guidance may be in the linked vendor advisories in the References section below.
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CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N
Exploit Intelligence
Low risk: more likely to be exploited than 11% of all known CVEs.
References
Related Vulnerabilities
Other CWE-863 (Incorrect Authorization) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2023-22518 | Critical | 9.8 | 100% | KEV + Ransom | Fix |
| CVE-2023-38035 | Critical | 9.8 | 100% | KEV + Ransom | - |
| CVE-2022-46169 | Critical | 9.8 | 100% | KEV | Fix |
| CVE-2024-38856 | Critical | 9.8 | 99% | KEV | Fix |
| CVE-2025-29927 | Critical | 9.1 | 99% | - | Fix |
| CVE-2020-36289 | Medium | 5.3 | 99% | - | Fix |
Common questions
How do I fix CVE-2026-16255?
No published fix for CVE-2026-16255 has been found yet. Check the linked vendor advisories for guidance as it becomes available.
Is CVE-2026-16255 being actively exploited?
Not that we know of. CVE-2026-16255 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.21% is the estimated probability that it will be exploited in the next 30 days. That is higher than 11% of all scored CVEs.
How severe is CVE-2026-16255?
CVE-2026-16255 has a CVSS v3 base score of 5.9, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
Embed a live status badge for CVE-2026-16255
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-10-22.