CPU exhaustion via empty printer model loop
Published Jul 23, 2026 · Updated Jul 23, 2026
Denial of service in libcupsfilters on Red Hat Enterprise Linux allows remote attackers to hang printing consumers through printer discovery. In cfIEEE1284NormalizeMakeModel, an empty MDL field makes the comparison length zero, so strncasecmp always matches and the loop makes no forward progress. Exploitation requires an attacker-controlled IEEE-1284 ID to reach cups-browsed over IPP or DNS-SD; the service is disabled by default, and success pins one CPU core until the consumer is killed.
Summary
What happened
Denial of service in libcupsfilters on Red Hat Enterprise Linux allows remote attackers to hang printing consumers through printer discovery. In cfIEEE1284NormalizeMakeModel, an empty MDL field makes the comparison length zero, so strncasecmp always matches and the loop makes no forward progress. Exploitation requires an attacker-controlled IEEE-1284 ID to reach cups-browsed over IPP or DNS-SD; the service is disabled by default, and success pins one CPU core until the consumer is killed.
The record
- CVE
- CVE-2026-64611
- Published
- Jul 23, 2026
- Updated
- Jul 23, 2026
- Vendor
- 389 Directory Server
- Product
- Red Hat Enterprise Linux 10
- Classifications
- CWE-835, T1499.004
- Attack vector
- adjacent
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 23, 2026CVE publishedPublication date reported by the CVE source.
- Jul 23, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
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
- OpenPrinting empty-MDL synthetic proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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