Unauthenticated service crash via URI size undercount
Published Apr 3, 2026 · Updated Apr 3, 2026
Heap-based buffer overflow in the CUPS scheduler through 2.4.16 allows remote attackers to crash cupsd via crafted IPP print jobs. The get_options function allocates the filter option string using ipp_length, which omits URI attributes, then copies attacker-controlled job-uuid and job-authorization-uri values into the undersized heap buffer without bounds checks. Any unauthenticated attacker able to submit a print job to a configured queue can interrupt the scheduler; the published assessment does not establish code execution.
Summary
What happened
Heap-based buffer overflow in the CUPS scheduler through 2.4.16 allows remote attackers to crash cupsd via crafted IPP print jobs. The get_options function allocates the filter option string using ipp_length, which omits URI attributes, then copies attacker-controlled job-uuid and job-authorization-uri values into the undersized heap buffer without bounds checks. Any unauthenticated attacker able to submit a print job to a configured queue can interrupt the scheduler; the published assessment does not establish code execution.
The record
- CVE
- CVE-2026-34979
- Published
- Apr 3, 2026
- Updated
- Apr 3, 2026
- Vendor
- OpenPrinting
- Product
- CUPS
- Classifications
- CWE-122, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 3, 2026CVE publishedPublication date reported by the CVE source.
- Apr 3, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=<= 2.4.16
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
- IPP URI undercount crash proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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