CVE-2026-124541
JSON::XS versions before 4.05 for Perl leak the decoded part of a rejected long string in decode_str
JSON::XS versions before 4.05 for Perl leak the decoded part of a rejected long string in decode_str. A string is decoded through a fixed-size buffer (16 KiB in 4.04), and each time the buffer fills its contents move into a new scalar. Nothing frees that scalar when the string is then rejected for a control character, an invalid escape, malformed UTF-8 or the end of the input. A process that keeps running after a failed decode retains the decoded part of each rejected string, with its size chosen by the sender. Repeated requests exhaust process memory.
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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