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Vulnerability · Published Oct 19, 2026 · Assigned by CPANSec

CVE-2026-110685Cpanel::JSON::XS versions before 4.80 for Perl leak the decoded arguments of a tagged value when its THAW method dies in decode_tag

Critical 9.1

In plain English

A critical-severity memory leak in Cpanel-JSON-XS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 44% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.1Critical
Exploit odds (30 days)0.5%top 56.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Cpanel::JSON::XS versions before 4.80 for Perl leak the decoded arguments of a tagged value when its THAW method dies in decode_tag. With allow_tags, a tagged value's class name and argument array are decoded and passed to the class's THAW method. Both are released only after THAW returns, so a THAW that dies leaves the whole decoded argument structure allocated. Each rejected document leaks data of a size the sender chooses, so a process that catches the error and keeps running exhausts its memory.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12libcpanel-json-xs-perlno fix listedDEBIAN-CVE-2026-110685
Debian:13libcpanel-json-xs-perlno fix listedDEBIAN-CVE-2026-110685
Debian:14libcpanel-json-xs-perl4.80-1DEBIAN-CVE-2026-110685
Ubuntu:22.04:LTSlibcpanel-json-xs-perlno fix listedUBUNTU-CVE-2026-110685
Ubuntu:24.04:LTSlibcpanel-json-xs-perlno fix listedUBUNTU-CVE-2026-110685
Ubuntu:26.04:LTSlibcpanel-json-xs-perlno fix listedUBUNTU-CVE-2026-110685
Ubuntu:26.10libcpanel-json-xs-perlno fix listedUBUNTU-CVE-2026-110685

Affected products (as reported)

VendorProductVersions
Cpanel-JSON-XS 0 – before 4.80

Weakness: CWE-401 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

References