CVE-2026-84739
HIGH 8.7GitLab has remediated an issue in GitLab CE/EE affecting all versions from 13.11 before 19.2.7, 19.3 before 19.3.3, and 19.4 before 19.4.1 that under certain conditions could have allowed an authenticated user to execute arbitrary JavaScript in the context of another user's browser session due to improper sanitization of path components in the merge request diff viewer.
Severe if exploited (CVSS 8.7), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
0.3%chance of exploitation in 30 days · 28th percentile
Impact if exploited
8.7CVSS 3.1 · HIGH
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityNone
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ⚠Privileges: Requires a low-privilege account
- ⚠User interaction: A user must take an action (click / open a file)
- ✓Complexity: No special conditions — reliably repeatable
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept
No public PoC is currently catalogued.
Search for new PoCs
Search GitHub now — results may be empty or unverified.
Tracked sources are checked daily for recent CVEs, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.
Data snapshot:
Weakness (CWE)
- CWE-79: : Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
References and research data (JSON)
Known Affected Software Configurations
| Vendor | Product | Version range |
|---|---|---|
| Gitlab | Gitlab | ≥ 13.11.0 and < 19.2.7 |
| Gitlab | Gitlab | ≥ 13.11.0 and < 19.2.7 |
| Gitlab | Gitlab | ≥ 19.3.0 and < 19.3.3 |
| Gitlab | Gitlab | ≥ 19.3.0 and < 19.3.3 |
| Gitlab | Gitlab | 19.4.0 |
| Gitlab | Gitlab | 19.4.0 |
All CVSS metrics
- HIGH 8.7 v3.1 · CNA Primary
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N - HIGH 8.7 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
References
Exploit-tagged references (not proof of a PoC)
- https://hackerone.com/reports/3938482 CVE record · GitLab · Updated 2026-09-29T09:34:28.011Z
NVD · CVE-2026-84739 · Updated 2026-10-05T17:06:09.640
Advisories
- https://docs.gitlab.com/releases/patches/patch-release-gitlab-19-4-1-released/ CVE record · GitLab · Updated 2026-09-29T09:34:28.011Z
NVD · CVE-2026-84739 · Updated 2026-10-05T17:06:09.640 - https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-88687 EUVD · EUVD-2026-88687
Technical & other
- https://gitlab.com/gitlab-org/gitlab/-/work_items/627316 CVE record · GitLab · Updated 2026-09-29T09:34:28.011Z
NVD · CVE-2026-84739 · Updated 2026-10-05T17:06:09.640