What’s Vulnerable › Vulnerabilities

CVE-2026-48959: IO::Uncompress::Unzip versions before 2.220 for Perl allow CPU exhaustion via per-byte read loop in fastForward

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-27 · updated 2026-07-24
• Weakness: CWE-407

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.

Affected products

• PMQS IO::Uncompress::Unzip: before 2.220 — fixed in 2.220

How to fix

Upgrade to a fixed version: PMQS IO::Uncompress::Unzip 2.220. Check the vendor advisory for mitigations.

References

• https://github.com/pmqs/IO-Compress/commit/68db44076f4c1a86a2ffe53a958eac6cabaf72e2.patch
• https://metacpan.org/release/PMQS/IO-Compress-2.220/changes
• http://www.openwall.com/lists/oss-security/2026/05/27/2

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