Service interruption via quadratic cookie unquoting
Published Aug 19, 2024 · Updated Nov 3, 2025
Algorithmic complexity in CPython's http.cookies module allows remote attackers to consume excessive CPU via crafted quoted cookie values. _unquote() repeatedly searches the remaining string with two regular expressions, causing quadratic work as backslash sequences accumulate. Exposure requires an application to pass attacker-controlled Cookie headers to http.cookies; repeated requests can delay or interrupt service.
Summary
What happened
Algorithmic complexity in CPython's http.cookies module allows remote attackers to consume excessive CPU via crafted quoted cookie values. _unquote() repeatedly searches the remaining string with two regular expressions, causing quadratic work as backslash sequences accumulate. Exposure requires an application to pass attacker-controlled Cookie headers to http.cookies; repeated requests can delay or interrupt service.
The record
- CVE
- CVE-2024-7592
- Published
- Aug 19, 2024
- Updated
- Nov 3, 2025
- Vendor
- Python Software Foundation
- Product
- CPython
- Classifications
- CWE-1333, CWE-400, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 19, 2024CVE publishedPublication date reported by the CVE source.
- Nov 3, 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 <3.8.20
- Affected versionversion=3.10.0 <3.10.15
- Affected versionversion=3.11.0 <3.11.10
- Affected versionversion=3.12.0 <3.12.6
- Affected versionversion=3.13.0a1 <3.13.0rc2
- Affected versionversion=3.9.0 <3.9.20
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
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
- Upstream http.cookies denial-of-service reproducerproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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