Authenticated service interruption via crafted Markdown rendering
Published Jun 8, 2021 · Updated Aug 3, 2024
Denial of service in affected GitLab CE/EE versions allows remote authenticated users to exhaust server CPU through crafted Markdown. The Markdown renderer performs disproportionately expensive parsing on repeated CSS and TypeScript fence sequences supplied through issues, merge requests, or the Markdown API. Low-privileged account access is required; concurrent malicious renders can deprive other users of service without altering or disclosing data.
Summary
What happened
Denial of service in affected GitLab CE/EE versions allows remote authenticated users to exhaust server CPU through crafted Markdown. The Markdown renderer performs disproportionately expensive parsing on repeated CSS and TypeScript fence sequences supplied through issues, merge requests, or the Markdown API. Low-privileged account access is required; concurrent malicious renders can deprive other users of service without altering or disclosing data.
The record
- CVE
- CVE-2021-22217
- Published
- Jun 8, 2021
- Updated
- Aug 3, 2024
- Vendor
- GitLab
- Product
- GitLab
- Classifications
- T1499.004
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 8, 2021CVE publishedPublication date reported by the CVE source.
- 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.
- Affected versionversion=<13.10.5
- Affected versionversion=>=13.11, <13.11.5
- Affected versionversion=>=13.12, <13.12.2
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
- Crafted Markdown CPU-exhaustion proof of conceptproof 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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