What’s Vulnerable › Vulnerabilities

CVE-2026-87719: Deserialization of Untrusted Data in GitLab

• Severity: critical (CVSS 9.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-12 · updated 2026-09-28
• Weakness: CWE-502

Description

GitLab has remediated an issue in GitLab EE affecting all versions from 18.3 before 18.11.12, 19.0 before 19.0.9, 19.1 before 19.1.8, 19.2 before 19.2.6, and 19.3 before 19.3.2 that under certain conditions could allow an authenticated user with Duo Chat access to obtain Advanced Search instance configurations and sensitive credentials using a specially crafted GraphQL subscription argument to bypass serialization and perform server object lookup.

Affected products

• GitLab: from 18.3.0 before 18.11.12; from 19.0.0 before 19.0.9; from 19.1.0 before 19.1.8; from 19.2.0 before 19.2.6; from 19.3.0 before 19.3.2 — fixed in 18.11.12, 19.0.9, 19.1.8, 19.2.6, 19.3.2

How to fix

Upgrade to a fixed version: GitLab 18.11.12, 19.0.9, 19.1.8, 19.2.6. Check the vendor advisory for mitigations.

References

• https://gitlab.com/gitlab-org/gitlab/-/work_items/628160
• https://hackerone.com/reports/4012289

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