CVE-2026-110684 Cpanel::JSON::XS versions from 3.0202 before 4.80 for Perl leak memory and retain overloaded objects when encoding values as strings in encode_stringify.
Attackers can cause memory exhaustion and denial of service by repeatedly encoding specific overloaded objects using the Cpanel::JSON::XS Perl library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-110684?
CVE-2026-110684 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 from 3.0202 before 4.80 for Perl leak memory and retain overloaded objects when encoding values as strings in encode_stringify.
encode_stringify writes a value in its string form under allow_stringify, under convert_blessed for objects without TO_JSON, and under allow_bignum. For an array or hash object with a "" overload, and from 4.20 a scalar object, it takes an extra reference that is never released, so the object and everything it references are never freed. From 4.10 it also never frees its copy of the string.
Repeatedly encoding data that contains such values grows process memory without bound.
Weakness: CWE-401
Which versions are affected by CVE-2026-110684?
How do I fix CVE-2026-110684?
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-2026-110684 being exploited?
There is no known exploitation of CVE-2026-110684 in the wild and no public exploit code.
Sources
Also known as AZL-109848, DEBIAN-CVE-2026-110684, GHSA-pjjg-2ww8-r6xm, UBUNTU-CVE-2026-110684.