Vulnerability Description
IO::Uncompress::Unzip versions before 2.220 for Perl allow CPU exhaustion via per-byte read loop in fastForward. fastForward() compares length $offset (the digit count of the offset, 1 to 19) against the chunk size $c instead of $offset itself, so $c shrinks from 16 KiB to 1-19 bytes per iteration. Extracting a named entry from an attacker supplied zip via IO::Uncompress::Unzip->new($zip, Name => $target) drives a per-byte read loop scaling with the entry's compressed size, up to the non-Zip64 4 GiB cap.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/pmqs/IO-Compress/commit/68db44076f4c1a86a2ffe53a958eac6cabaf7
- https://metacpan.org/release/PMQS/IO-Compress-2.220/changes
- http://www.openwall.com/lists/oss-security/2026/05/27/2
FAQ
What is CVE-2026-48959?
CVE-2026-48959 is a vulnerability with a CVSS score of 7.5 (HIGH). IO::Uncompress::Unzip versions before 2.220 for Perl allow CPU exhaustion via per-byte read loop in fastForward. fastForward() compares length $offset (the digit count of the offset, 1 to 19) against...
How severe is CVE-2026-48959?
CVE-2026-48959 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-48959?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.