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.
Attackers can cause a segmentation fault and crash applications using Cpanel::JSON::XS by sending deeply nested tagged JSON values when allow_tags is enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-110673?
CVE-2026-110673 is a high-severity denial of service vulnerability, published on 19 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-674
Which versions are affected by CVE-2026-110673?
How do I fix CVE-2026-110673?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-110673 being exploited?
There is no known exploitation of CVE-2026-110673 in the wild and no public exploit code.
Sources
Also known as AZL-109842, DEBIAN-CVE-2026-110673, GHSA-fgcx-mvpm-hff9, UBUNTU-CVE-2026-110673.