Loop with Unreachable Exit Condition ('Infinite Loop') Affecting perl-IO-Compress package, versions <0:2.061-2.amzn2.0.1


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.55% (46th percentile)

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  • Snyk IDSNYK-AMZN2-PERLIOCOMPRESS-17406586
  • published23 Jun 2026
  • disclosed27 May 2026

Introduced: 27 May 2026

CVE-2026-48959  (opens in a new tab)
CWE-835  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2 perl-IO-Compress to version 0:2.061-2.amzn2.0.1 or higher.
This issue was patched in ALAS2-2026-3355.

NVD Description

Note: Versions mentioned in the description apply only to the upstream perl-IO-Compress package and not the perl-IO-Compress package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2 relevant fixed versions and status.

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 Base Scores

version 3.1