JSON::XS versions from 3.0 before 4.05 for Perl read freed stack memory when a FREEZE result's serialisation grows the Perl stack under allow_tags in encode_rv

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-129115
StatePUBLISHED
AssignerCPANSec
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-14 12:17:44 UTC
Updated2026-11-14 12:17:44 UTC
DescriptionJSON::XS versions from 3.0 before 4.05 for Perl read freed stack memory when a FREEZE result's serialisation grows the Perl stack under allow_tags in encode_rv. With allow_tags, an object's FREEZE method is called in list context and each returned value is encoded through a saved Perl stack pointer. When encoding a returned value calls back into Perl, through TO_JSON under convert_blessed or another FREEZE, and that callback grows the stack, the stack is reallocated while the saved pointer still refers to the freed block. Encoding such objects reads freed memory, and encode can return undef without an error.

Risk And Classification

Problem Types: CWE-416 | CWE-416 CWE-416 Use After Free

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

Vendor Comments And Credit

Discovery Credit

CNA: Albert Gierlach (rivit) (en)

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.

© CVE.report 2026

Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. It is the responsibility of user to evaluate the accuracy, completeness or usefulness of any information, opinion, advice or other content. EACH USER WILL BE SOLELY RESPONSIBLE FOR ANY consequences of his or her direct or indirect use of this web site. ALL WARRANTIES OF ANY KIND ARE EXPRESSLY DISCLAIMED. This site will NOT BE LIABLE FOR ANY DIRECT, INDIRECT or any other kind of loss.

CVE, CWE, and OVAL are registred trademarks of The MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. This site includes MITRE data granted under the following license.

Free CVE JSON API cve.report/api

CVE.report and Source URL Uptime Status status.cve.report