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Vulnerability · Published Oct 19, 2026 · Assigned by CPANSec

CVE-2026-110677Cpanel::JSON::XS versions from 4.28 before 4.80 for Perl leak the array collecting duplicate key values under dupkeys_as_arrayref in decode_hv

High 7.5

In plain English

A high-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 42% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.5%top 58.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Cpanel::JSON::XS versions from 4.28 before 4.80 for Perl leak the array collecting duplicate key values under dupkeys_as_arrayref in decode_hv. With dupkeys_as_arrayref, the values of a duplicate object key are collected into a new array. An extra reference is never released, so the array and every value in it outlive the decoded structure. The array also leaks when decoding fails after a duplicate key. Repeatedly decoding untrusted JSON with a duplicate key holding a large value exhausts process memory.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12libcpanel-json-xs-perlno fix listedDEBIAN-CVE-2026-110677
Debian:13libcpanel-json-xs-perlno fix listedDEBIAN-CVE-2026-110677
Debian:14libcpanel-json-xs-perl4.80-1DEBIAN-CVE-2026-110677
Ubuntu:22.04:LTSlibcpanel-json-xs-perlno fix listedUBUNTU-CVE-2026-110677
Ubuntu:24.04:LTSlibcpanel-json-xs-perlno fix listedUBUNTU-CVE-2026-110677
Ubuntu:26.04:LTSlibcpanel-json-xs-perlno fix listedUBUNTU-CVE-2026-110677
Ubuntu:26.10libcpanel-json-xs-perlno fix listedUBUNTU-CVE-2026-110677

Affected products (as reported)

VendorProductVersions
Cpanel-JSON-XS 4.28 – before 4.80

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

References