JSON::XS versions before 4.05 for Perl leak the decoded part of a rejected long string in decode_str

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-124541
StatePUBLISHED
AssignerCPANSec
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-14 12:17:43 UTC
Updated2026-11-14 12:17:43 UTC
DescriptionJSON::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.

Risk And Classification

Problem Types: CWE-401 | CWE-401 CWE-401 Missing Release of Memory after Effective Lifetime

References

ReferenceSourceLinkTags
metacpan.org/release/MLEHMANN/JSON-XS-4.05/changes 9b29abf9-4ab0-4765-b253-1875cd9b441e metacpan.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

SourceTimeEvent
CNA2026-11-13T00:00:00.000ZVersion 4.05 released with fix.

Solutions

CNA: Upgrade to JSON-XS 4.05 or later.

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