Service interruption via quadratic Markdown parsing
Published Jul 13, 2023 · Updated Oct 30, 2024
Algorithmic complexity flaws in GitHub cmark-gfm 0.29.0.gfm.11 allow remote attackers to interrupt services with crafted Markdown. Table rendering repeatedly walks a linked list for each cell, omitted columns expand linear input into a quadratic table, and footnote parsing rescans every open block for each empty line. Exposure requires an application to process attacker-controlled Markdown with the table or footnotes extension; the resulting CPU and memory exhaustion can hang the consuming service.
Summary
What happened
Algorithmic complexity flaws in GitHub cmark-gfm 0.29.0.gfm.11 allow remote attackers to interrupt services with crafted Markdown. Table rendering repeatedly walks a linked list for each cell, omitted columns expand linear input into a quadratic table, and footnote parsing rescans every open block for each empty line. Exposure requires an application to process attacker-controlled Markdown with the table or footnotes extension; the resulting CPU and memory exhaustion can hang the consuming service.
The record
- CVE
- CVE-2023-37463
- Published
- Jul 13, 2023
- Updated
- Oct 30, 2024
- Vendor
- Product
- cmark-gfm
- Classifications
- CWE-407, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 13, 2023CVE publishedPublication date reported by the CVE source.
- Oct 30, 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=< 0.29.0.gfm.12
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
- GitHub Security Lab crafted-Markdown 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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