CVE-2026-48961: IO::Compress versions from 2.207 before 2.220 for Perl ship a zipdetails CLI tool that crashes with undefined subroutine on Info-ZIP Unix Extra Field with 8-byte UID or GID

[Stig Palmquist <stig () stig io>]

========================================================================
CVE-2026-48961                                       CPAN Security Group
========================================================================

        CVE ID:  CVE-2026-48961
  Distribution:  IO-Compress
      Versions:  from 2.207 before 2.220

      MetaCPAN:  https://metacpan.org/dist/IO-Compress
      VCS Repo:  https://github.com/pmqs/IO-Compress


IO::Compress versions from 2.207 before 2.220 for Perl ship a
zipdetails CLI tool that crashes with undefined subroutine on Info-ZIP
Unix Extra Field with 8-byte UID or GID

Description
-----------
IO::Compress versions from 2.207 before 2.220 for Perl ship a
zipdetails CLI tool that crashes with undefined subroutine on Info-ZIP
Unix Extra Field with 8-byte UID or GID.

When decode_ux() in bin/zipdetails handles an Info-ZIP Unix Extra Field
(tag 0x7875) with UID Size or GID Size set to 8, causing zipdetails to
decode an 8-byte UID or GID value, it dispatches through
decodeLitteEndian(), which calls a misnamed helper unpackValueQ. The
actual function defined in the same file is unpackValue_Q (with
underscore); the call raises 'Undefined subroutine &main::unpackValueQ'
and the script exits with status 255.

Library callers of IO::Compress and IO::Uncompress are not affected;
the defect is in the bundled CLI tool.

Problem types
-------------
- CWE-755 Improper Handling of Exceptional Conditions

Solutions
---------
Upgrade to IO-Compress 2.220 or later.


References
----------
https://github.com/pmqs/IO-Compress/commit/33c89d03d6e746ed2ead4f2f6570d47864c61bc7.patch
https://metacpan.org/release/PMQS/IO-Compress-2.220/changes

Timeline
--------
- 2026-05-14: Issue reported.
- 2026-05-16: Version 2.220 released.