Application crash via unvalidated AST byte fields
Published Mar 28, 2023 · Updated Feb 18, 2025
Denial of service in Comrak before 0.17.0 allows remote attackers to crash applications that render attacker-controlled programmatic ASTs. The HTML formatter trusts byte-backed NodeHtmlBlock, FootnoteReference, and NodeCodeBlock fields as valid UTF-8, allowing malformed values to reach unchecked conversion, indexing, or unwrap operations. Exploitation requires a consuming application to build AST nodes from attacker-controlled data; successful input terminates the affected process.
Summary
What happened
Denial of service in Comrak before 0.17.0 allows remote attackers to crash applications that render attacker-controlled programmatic ASTs. The HTML formatter trusts byte-backed NodeHtmlBlock, FootnoteReference, and NodeCodeBlock fields as valid UTF-8, allowing malformed values to reach unchecked conversion, indexing, or unwrap operations. Exploitation requires a consuming application to build AST nodes from attacker-controlled data; successful input terminates the affected process.
The record
- CVE
- CVE-2023-28631
- Published
- Mar 28, 2023
- Updated
- Feb 18, 2025
- Vendor
- kivikakk
- Product
- Comrak
- Classifications
- CWE-755, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 28, 2023CVE publishedPublication date reported by the CVE source.
- Feb 18, 2025Record 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=< 0.17.0
What conditions does exploitation require?
What is affected?
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 malformed AST proof of conceptproof of concept · demonstrated
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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