CVE-2026-110673: Cpanel::JSON::XS versions before 4.80 for Perl allow stack exhaustion via nested tagged values under allow_tags in decode_tag

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-674

Description

Cpanel::JSON::XS versions before 4.80 for Perl allow stack exhaustion via nested tagged values under allow_tags in decode_tag. With allow_tags, "(" starts a tagged value. Its tag and value are decoded recursively, and each can start another tagged value. Unlike arrays and objects, this nesting is not counted against max_depth. A run of "(" bytes exhausts the C stack and triggers an uncatchable segmentation fault regardless of max_depth.

Affected products

Cpanel-JSON-XS: 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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