CVE-2021-22197Network attack vector

Authenticated service interruption via merge-request branch cycle

Published Apr 2, 2021 · Updated Aug 3, 2024

Infinite-loop denial of service in affected GitLab CE/EE releases allows remote authenticated users to interrupt service via a cyclic merge request. When a merge request's source and target branches point to each other, merge-request processing follows the cycle without enforcing an exit condition. The trigger requires an authenticated account with specific project rights and access to the merge request; the published consequence is limited to availability.

CVSS severity3.5
Low
EPSS probability0.84%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Infinite-loop denial of service in affected GitLab CE/EE releases allows remote authenticated users to interrupt service via a cyclic merge request. When a merge request's source and target branches point to each other, merge-request processing follows the cycle without enforcing an exit condition. The trigger requires an authenticated account with specific project rights and access to the merge request; the published consequence is limited to availability.

The record

CVE
CVE-2021-22197
Published
Apr 2, 2021
Updated
Aug 3, 2024
Vendor
GitLab
Product
GitLab
Classifications
CWE-835, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 2, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>=10.6, <13.8.7
  2. Affected versionversion=>=13.10, <13.10.1
  3. Affected versionversion=>=13.9, <13.9.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

GitLab · GitLabversion=>=10.6, <13.8.7; version=>=13.10, <13.10.1; version=>=13.9, <13.9.5

Published CVSS scores

4.0NIST NVDAV:N/AC:L/Au:S/C:N/I:N/A:P
4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
3.5GitLab Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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