What’s Vulnerable › Vulnerabilities

CVE-2021-39880

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-10-05 · updated 2026-06-17

Description

A Denial Of Service vulnerability in the apollo_upload_server Ruby gem in GitLab CE/EE all versions starting from 11.9 before 14.0.9, all versions starting from 14.1 before 14.1.4, and all versions starting from 14.2 before 14.2.2 allows an attacker to deny access to all users via specially crafted requests to the apollo_upload_server middleware.

Affected products

• GitLab: from 11.9.0 (excl.) before 14.0.9; from 11.9.0 before 14.0.9; from 14.1.0 (excl.) before 14.1.4; from 14.1.0 before 14.1.4; from 14.2.0 before 14.2.2 — fixed in 14.0.9, 14.1.4, 14.2.2

How to fix

Upgrade to a fixed version: GitLab 14.0.9, 14.1.4, 14.2.2. Check the vendor advisory for mitigations.

References

• https://gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-39880.json
• https://gitlab.com/gitlab-org/gitlab/-/issues/330561
• https://hackerone.com/reports/1181284
• https://gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-39880.json
• https://gitlab.com/gitlab-org/gitlab/-/issues/330561
• https://hackerone.com/reports/1181284

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