CVE-2026-124540
JSON::XS versions before 4.05 for Perl allow stack exhaustion via nested tagged values under allow_tags in decode_tag
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.
Fixes and workarounds
Fix
Upgrade to JSON-XS 4.05 or later.
Source: CNA: CPANSecAffected products and versions
| Product | Versions | Authority |
|---|---|---|
JSON-XS
cpan |
≥ 0; < 4.05 (affected, custom)
Other versions: unaffected |
CNA: CPANSec |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
No CVSS assessment reported. An unscored record is not a low-severity determination.
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://metacpan.org/release/MLEHMANN/JSON-XS-4.05/changesCNA: CPANSec · release-notes
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