Service interruption via cubic autolink parsing
Published Feb 12, 2023 · Updated Aug 5, 2024
Regular expression denial of service in Khan Academy simple-markdown 0.6.0 allows remote attackers to interrupt applications via crafted markdown. The autolink rule's inlineRegex permits colons inside the URI-scheme capture, repeatedly rescanning crafted angle-bracket and slash sequences with cubic complexity. Exposure requires a consuming application to pass attacker-controlled markdown to the default inline parser, causing prolonged parsing and excessive CPU use.
Summary
What happened
Regular expression denial of service in Khan Academy simple-markdown 0.6.0 allows remote attackers to interrupt applications via crafted markdown. The autolink rule's inlineRegex permits colons inside the URI-scheme capture, repeatedly rescanning crafted angle-bracket and slash sequences with cubic complexity. Exposure requires a consuming application to pass attacker-controlled markdown to the default inline parser, causing prolonged parsing and excessive CPU use.
The record
- CVE
- CVE-2019-25102
- Published
- Feb 12, 2023
- Updated
- Aug 5, 2024
- Vendor
- Khan Academy
- Product
- simple-markdown
- Classifications
- CWE-1333, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 12, 2023CVE publishedPublication date reported by the CVE source.
- Aug 5, 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=0.6.0
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
- Autolink ReDoS timing demonstrationproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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