CVE-2025-12734
Improper Encoding or Escaping of Output in GitLab
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 15.6 before 18.4.6, 18.5 before 18.5.4, and 18.6 before 18.6.2 that could have allowed an authenticated user to, under certain conditions, render content in dialogs to other users by injecting malicious HTML content into merge request titles.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- Required
What an attacker can affect
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Improper Encoding or Escaping of Output in GitLab
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 15.6 before 18.4.6, 18.5 before 18.5.4, and 18.6 before 18.6.2 that could have allowed an authenticated user to, under certain conditions, render content in dialogs to other users by injecting malicious HTML content into merge request titles.
- Record
CVE-2025-12734- CVSS 3.1
- 3.5 Low
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N - Weakness
- CWE-116
- Updated
- 2026-11-02
EUVDEUVD-2025-202668
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 15.6 before 18.4.6, 18.5 before 18.5.4, and 18.6 before 18.6.2 that could have allowed an authenticated user to, under certain conditions, render content in dialogs to other users by injecting malicious HTML content into merge request titles.
- Record
EUVD-2025-202668- CVSS 3.1
- 3.5 Low
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-cpx5-2q84-prc5
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 15.6 before 18.4.6, 18...
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 15.6 before 18.4.6, 18.5 before 18.5.4, and 18.6 before 18.6.2 that could have allowed an authenticated user to leak sensitive information from specifically crafted merge request titles.
- Record
GHSA-cpx5-2q84-prc5- CVSS 3.1
- 3.5 Low
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N - Weakness
- CWE-116
- Updated
- 2026-11-02
NVD
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 15.6 before 18.4.6, 18.5 before 18.5.4, and 18.6 before 18.6.2 that could have allowed an authenticated user to, under certain conditions, render content in dialogs to other users by injecting malicious HTML content into merge request titles.
- Record
CVE-2025-12734- CVSS 3.1
- 3.5 Low
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N - Weakness
- CWE-116
- Updated
- 2026-11-02
OSV
Improper Encoding or Escaping of Output in GitLab
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 15.6 before 18.4.6, 18.5 before 18.5.4, and 18.6 before 18.6.2 that could have allowed an authenticated user to, under certain conditions, render content in dialogs to other users by injecting malicious HTML content into merge request titles.
- Record
CVE-2025-12734- CVSS 3.1
- 3.5 Low
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N - Weakness
- CWE-116
- Updated
- 2026-11-02
OSVUBUNTU-CVE-2025-12734
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 15.6 before 18.4.6, 18.5 before 18.5.4, and 18.6 before 18.6.2 that could have allowed an authenticated user to, under certain conditions, render content in dialogs to other users by injecting malicious HTML content into merge request titles.
- Record
UBUNTU-CVE-2025-12734- CVSS 3.1
- 3.5 Low
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N - Updated
- 2026-11-02
OSVBIT-gitlab-2025-12734 No score
Improper Encoding or Escaping of Output in GitLab
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 15.6 before 18.4.6, 18.5 before 18.5.4, and 18.6 before 18.6.2 that could have allowed an authenticated user to, under certain conditions, render content in dialogs to other users by injecting malicious HTML content into merge request titles.
- Record
BIT-gitlab-2025-12734- Updated
- 2026-11-02
Affected products
Affected packages
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-12734 is a low vulnerability (CVSS 3.5) in Gitlab, published December 11, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.27%, the 19th percentile. Fixed in gitlab 18.4.6.
References
gitlab.com/gitlab-org/gitlab/-/issues/579573
hackerone.com/reports/3379381
about.gitlab.com/releases/2025/12/10/patch-release-gitlab-18-6-2-released
nvd.nist.gov/vuln/detail/CVE-2025-12734
github.com/advisories/GHSA-cpx5-2q84-prc5
ubuntu.com/security/CVE-2025-12734
cve.org/CVERecord?id=CVE-2025-12734