CVE-2026-124540 PUBLISHED

JSON::XS versions before 4.05 for Perl allow stack exhaustion via nested tagged values under allow_tags in decode_tag

Assigner: CPANSec
Reserved: 08.11.2026 Published: 14.11.2026 Updated: 14.11.2026

JSON::XS versions before 4.05 for Perl allow stack exhaustion via nested tagged values under allow_tags in decode_tag.

With allow_tags, "(" starts a tagged value. Its tag and value are decoded recursively, and each can start another tagged value. Unlike arrays and objects, this nesting is not counted against max_depth.

A run of "(" bytes exhausts the C stack and triggers an uncatchable segmentation fault regardless of max_depth.

Product Status

Package Collection https://cpan.org/modules
Package Name JSON-XS
Versions Default: unaffected
  • affected from 0 to 4.05 (excl.)

Solutions

Upgrade to JSON-XS 4.05 or later.

References

Problem Types

  • CWE-674 Uncontrolled Recursion CWE