CVE-2026-1659

Description

GitLab has remediated an issue in GitLab CE/EE affecting all versions from 9.0 before 18.9.7, 18.10 before 18.10.6, and 18.11 before 18.11.3 that could have allowed an unauthenticated user to cause denial of service by sending specially crafted requests due to insufficient input validation.

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CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0005

Probability of exploitation

0.16%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-770 CWE-770

Affected Products

Vendor	Product	Versions
gitlab	gitlab	9.0.0 — 18.9.7
gitlab	gitlab	9.0.0 — 18.9.7
gitlab	gitlab	18.10.0 — 18.10.6
gitlab	gitlab	18.10.0 — 18.10.6
gitlab	gitlab	18.11.0 — 18.11.3
gitlab	gitlab	18.11.0 — 18.11.3

References

Other References

https://about.gitlab.com/releases/2026/05/13/patch-release-gitlab-18-11-3-released/ https://gitlab.com/gitlab-org/gitlab/-/work_items/588201 https://hackerone.com/reports/3519824

Frequently Asked Questions

What is CVE-2026-1659? +

GitLab has remediated an issue in GitLab CE/EE affecting all versions from 9.0 before 18.9.7, 18.10 before 18.10.6, and 18.11 before 18.11.3 that could have allowed an unauthenticated user to cause denial of service by sending specially crafted requests due to insufficient input validation. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-1659? +

CVE-2026-1659 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0005, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-1659? +

CVE-2026-1659 affects products from gitlab, specifically: gitlab. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-1659? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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