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Description

GitLab has remediated an issue in GitLab CE/EE affecting all versions from 10.6 before 18.7.6, 18.8 before 18.8.6, and 18.9 before 18.9.2 that could have allowed an authenticated user, when the `markdown_placeholders` feature flag was enabled, to inject JavaScript in a browser due to improper sanitization of placeholder content in markdown processing.

PUBLISHED Reserved 2026-01-16 | Published 2026-03-11 | Updated 2026-03-12 | Assigner GitLab




HIGH: 8.7CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

Problem types

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Product status

Default status
unaffected

10.6 (semver) before 18.7.6
affected

18.8 (semver) before 18.8.6
affected

18.9 (semver) before 18.9.2
affected

Credits

Thanks [yvvdwf](https://hackerone.com/yvvdwf) for reporting this vulnerability through our HackerOne bug bounty program finder

References

hackerone.com/reports/3502450 (HackerOne Bug Bounty Report #3502450) technical-description exploit permissions-required

gitlab.com/gitlab-org/gitlab/-/work_items/586478

about.gitlab.com/...11/patch-release-gitlab-18-9-2-released/

cve.org (CVE-2026-1090)

nvd.nist.gov (CVE-2026-1090)

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