Printing-service hang via incomplete request line
Published Nov 29, 2025 · Updated Dec 3, 2025
Denial of service in cupsd in OpenPrinting CUPS before 2.4.15 allows local users to halt printing with a slowly delivered request. The single-threaded scheduler waits for a complete HTTP request line, letting one client drip bytes slowly enough to block processing for every other client. The default listener accepts only local connections; remote attackers need CUPS exposed to untrusted networks, and exploitation makes cupsd unresponsive without reported data access or modification.
Summary
What happened
Denial of service in cupsd in OpenPrinting CUPS before 2.4.15 allows local users to halt printing with a slowly delivered request. The single-threaded scheduler waits for a complete HTTP request line, letting one client drip bytes slowly enough to block processing for every other client. The default listener accepts only local connections; remote attackers need CUPS exposed to untrusted networks, and exploitation makes cupsd unresponsive without reported data access or modification.
The record
- CVE
- CVE-2025-58436
- Published
- Nov 29, 2025
- Updated
- Dec 3, 2025
- Vendor
- OpenPrinting
- Product
- CUPS
- Classifications
- CWE-400, T1499.004
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Nov 29, 2025CVE publishedPublication date reported by the CVE source.
- Dec 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=< 2.4.15
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
- OpenPrinting slow-client cupsd PoCproof 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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