What is CVE-2026-3988?
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 18.5 before 18.8.7, 18.9 before 18.9.3, and 18.10 before 18.10.1 that could have allowed an unauthenticated user to cause a denial of service by making the GitLab instance unresponsive due to improper input validation in GraphQL request processing.
The record classifies CVE-2026-3988 under weakness class CWE-407. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 212 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 7.5 — HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS (FIRST)
- 0.8% probability of exploitation in the next 30 days, higher than 57.0% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 6/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-03-25
Is CVE-2026-3988 being exploited?
It currently carries a trending score of 19 in the Threadlinqs vulnerability feed.
Affected products and versions
- GitLab: GitLab
How to fix CVE-2026-3988
No vendor patch reference has been recorded for CVE-2026-3988 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-3988
1 tracked threat in the Threadlinqs corpus references CVE-2026-3988, either in the campaign’s CVE list or as an indicator on the campaign record.
Sources
Enriched from CVE.org, FIRST EPSS. Last verified by Threadlinqs on .