Denial of service via Markdown rendering exhaustion
Published Oct 17, 2022 · Updated May 13, 2025
Denial of service in GitLab CE/EE before 15.1.6, 15.2 through 15.2.3, and 15.3 through 15.3.1 allows remote attackers to exhaust CPU. ReferenceExtractor passes attacker-controlled issue-description text to Renderer.cache_collection_render, where deeply repeated Markdown image syntax consumes a CPU core until the 60-second request timeout. The unauthenticated Markdown preview API exposes the path remotely; parallel requests can occupy multiple CPU cores and make the server unavailable without disclosing or altering data.
Summary
What happened
Denial of service in GitLab CE/EE before 15.1.6, 15.2 through 15.2.3, and 15.3 through 15.3.1 allows remote attackers to exhaust CPU. ReferenceExtractor passes attacker-controlled issue-description text to Renderer.cache_collection_render, where deeply repeated Markdown image syntax consumes a CPU core until the 60-second request timeout. The unauthenticated Markdown preview API exposes the path remotely; parallel requests can occupy multiple CPU cores and make the server unavailable without disclosing or altering data.
The record
- CVE
- CVE-2022-2931
- Published
- Oct 17, 2022
- Updated
- May 13, 2025
- Vendor
- GitLab
- Product
- GitLab
- Classifications
- CWE-400, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Oct 17, 2022CVE publishedPublication date reported by the CVE source.
- May 13, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=<15.1.6
- Affected versionversion=>=15.2, <15.2.4
- Affected versionversion=>=15.3, <15.3.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
- GitLab Markdown CPU-exhaustion reproductionproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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