Process hang via catastrophic validation regex backtracking
Published Apr 3, 2023 · Updated Feb 13, 2025
ReDoS in ConfigObj before 5.0.9 allows attackers to hang a consuming process through a crafted validation check string. Validator._func_re applies nested, overlapping wildcards while parsing the check name and arguments, causing catastrophic backtracking when a long malformed string fails to match. Exploitation requires control over a validation specification loaded from a server-side configuration file, and the resulting CPU exhaustion interrupts only the consuming process.
Summary
What happened
ReDoS in ConfigObj before 5.0.9 allows attackers to hang a consuming process through a crafted validation check string. Validator._func_re applies nested, overlapping wildcards while parsing the check name and arguments, causing catastrophic backtracking when a long malformed string fails to match. Exploitation requires control over a validation specification loaded from a server-side configuration file, and the resulting CPU exhaustion interrupts only the consuming process.
The record
- CVE
- CVE-2023-26112
- Published
- Apr 3, 2023
- Updated
- Feb 13, 2025
- Vendor
- ConfigObj Project
- Product
- ConfigObj
- Classifications
- CWE-1333, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 3, 2023CVE publishedPublication date reported by the CVE source.
- Feb 13, 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?
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- Affected versionversion=0 <*
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
- ConfigObj catastrophic-backtracking trigger scriptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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