CVE-2021-39880

apollo_upload_server has Denial of Service vulnerability

6.5 MediumFix available

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.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: Low
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: High

Exploit likelihood

2.07%Up 1.0 points since Oct 6, 2021

What each source reports

CVE List Score used 6.5

Record: CVE-2021-39880
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

EUVDEUVD-2022-5513 6.5

Record: EUVD-2022-5513
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-03

GitHub AdvisoriesGHSA-w6pv-c757-6rgr 6.5

apollo_upload_server has Denial of Service vulnerability

A Denial Of Service vulnerability in the apollo_upload_server Ruby gem in GitLab CE/EE version 11.11 and above allows an attacker to deny access to all users via specially crafted requests to the apollo_upload_server middleware.

Record: GHSA-w6pv-c757-6rgr
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

NVD 6.5

Record: CVE-2021-39880
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0: 4.0 MediumAV:N/AC:L/Au:S/C:N/I:N/A:P
Updated: 2026-11-02

OSV 6.5

Record: CVE-2021-39880
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVDEBIAN-CVE-2021-39880 6.5

Record: DEBIAN-CVE-2021-39880
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVGHSA-w6pv-c757-6rgr 6.5

apollo_upload_server has Denial of Service vulnerability

Record: GHSA-w6pv-c757-6rgr
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVUBUNTU-CVE-2021-39880 6.5

Record: UBUNTU-CVE-2021-39880
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVBIT-gitlab-2021-39880 No score

Record: BIT-gitlab-2021-39880
Updated: 2026-11-02

Affected products

gitlab

Affected packages

Affected packages
Package	Affected	Fixed
`apollo_upload_server` RubyGems	before 2.1.0	2.1.0
`gitlab` Bitnami	11.9.0 up to 14.0.9, 14.1.0 up to 14.1.4, 14.2.0 up to 14.2.2	14.0.914.1.414.2.2
`ruby-apollo-upload-server` Debian:12	before 2.1.0-1	2.1.0-1
`ruby-apollo-upload-server` Debian:13	before 2.1.0-1	2.1.0-1
`ruby-apollo-upload-server` Debian:14	before 2.1.0-1	2.1.0-1
`apollo_upload_server` RubyGems	before 2.1.0, plus listed versions 0.1.01.0.02.0.02.0.0.alpha.12.0.0.alpha.2 Show 12 moreShow less 2.0.0.alpha.32.0.0.alpha.42.0.0.alpha.52.0.0.alpha.62.0.0.beta.12.0.0.beta.22.0.0.beta.32.0.12.0.22.0.32.0.42.0.5	2.1.0
`gitlab` Ubuntu:16.04:LTS	All versions, plus listed versions 8.4.3+dfsg-98.4.3+dfsg-128.5.8+dfsg-5	None known

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-39880 is a medium vulnerability (CVSS 6.5) in Gitlab, published October 5, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.07%, the 81st percentile. Fixed in apollo_upload_server 2.1.0.

References

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