CVE-2026-110677: 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

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-19 · updated 2026-10-29
Weakness: CWE-401

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 products

Cpanel-JSON-XS: from 4.28 before 4.80 — fixed in 4.80

How to fix

Upgrade to a fixed version: Cpanel-JSON-XS 4.80. Check the vendor advisory for mitigations.

References

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