Client service interruption via Set-Cookie regex backtracking
Published Dec 22, 2022 · Updated Apr 15, 2025
Regular expression denial of service in Python Charmers Future 0.18.2 and earlier allows remote attackers to interrupt clients via Set-Cookie. The http.cookiejar.LOOSE_HTTP_DATE_RE expression uses overlapping whitespace repetitions that backtrack excessively on long space sequences. Exploitation requires a client using the backported cookie parser to process a crafted Set-Cookie header from a malicious web server, consuming CPU and interrupting service.
Summary
What happened
Regular expression denial of service in Python Charmers Future 0.18.2 and earlier allows remote attackers to interrupt clients via Set-Cookie. The http.cookiejar.LOOSE_HTTP_DATE_RE expression uses overlapping whitespace repetitions that backtrack excessively on long space sequences. Exploitation requires a client using the backported cookie parser to process a crafted Set-Cookie header from a malicious web server, consuming CPU and interrupting service.
The record
- CVE
- CVE-2022-40899
- Published
- Dec 22, 2022
- Updated
- Apr 15, 2025
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-400, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 22, 2022CVE publishedPublication date reported by the CVE source.
- Apr 15, 2025Record updatedLatest update available in the CVE record.
Exploitability
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Attacks
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