CVE-2026-16255
Incorrect Authorization in GitLab
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Incorrect Authorization in GitLab
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.
- Record
CVE-2026-16255- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N - Weakness
- CWE-863
- Updated
- 2026-11-02
EUVDEUVD-2026-107676
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.
- Record
EUVD-2026-107676- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-m22v-48hx-jv7m
GitLab has remediated an issue in GitLab EE affecting all versions from 12.0 before 19.3.6, 19.4...
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.
- Record
GHSA-m22v-48hx-jv7m- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N - Weakness
- CWE-863
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-16255- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N - CVSS 3.1
- 7.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N - Weakness
- CWE-863
- Updated
- 2026-11-05
OSV
Incorrect Authorization in GitLab
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.
- Record
CVE-2026-16255- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N - Weakness
- CWE-863
- Updated
- 2026-11-05
OSVBIT-gitlab-2026-16255 No score
Incorrect Authorization in GitLab
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.
- Record
BIT-gitlab-2026-16255- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
gitlabBitnami |
12.0.0 up to 19.3.6, 19.4.0 up to 19.4.3, 19.5.0 up to 19.5.1 | 19.3.619.4.319.5.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| facts | NVD | |
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-16255 is a medium vulnerability (CVSS 5.9) in Gitlab, published October 21, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.26%, the 17th percentile. Fixed in gitlab 19.3.6.
References
gitlab.com/gitlab-org/gitlab/-/work_items/606479
hackerone.com/reports/3809350
docs.gitlab.com/releases/patches/patch-release-gitlab-19-5-1-released
nvd.nist.gov/vuln/detail/CVE-2026-16255
github.com/advisories/GHSA-m22v-48hx-jv7m