Service interruption via inline-code regex backtracking
Published Feb 12, 2023 · Updated Aug 5, 2024
Regular expression denial of service in Khan Academy simple-markdown 0.5.1 allows remote attackers to interrupt service via crafted inline code. The inlineCode rule lets spaces match both adjacent optional-whitespace groups and the captured body, causing catastrophic backtracking on long space-heavy strings. The consuming application must parse attacker-controlled Markdown; the resulting CPU exhaustion stalls parsing without reported data access or modification.
Summary
What happened
Regular expression denial of service in Khan Academy simple-markdown 0.5.1 allows remote attackers to interrupt service via crafted inline code. The inlineCode rule lets spaces match both adjacent optional-whitespace groups and the captured body, causing catastrophic backtracking on long space-heavy strings. The consuming application must parse attacker-controlled Markdown; the resulting CPU exhaustion stalls parsing without reported data access or modification.
The record
- CVE
- CVE-2019-25103
- Published
- Feb 12, 2023
- Updated
- Aug 5, 2024
- Vendor
- Khan Academy
- Product
- simple-markdown
- Classifications
- CWE-1333, T1499.004
- Attack vector
- network
- Privileges
- Unavailable
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?
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- Affected versionversion=0.5.1
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
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Technologies
Your stack
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Your stack
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