CVE-2026-110685 Cpanel::JSON::XS versions before 4.80 for Perl leak the decoded arguments of a tagged value when its THAW method dies in decode_tag.
A memory leak in Cpanel::JSON::XS allows attackers to exhaust server memory by sending crafted JSON with failing THAW methods, causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-110685?
CVE-2026-110685 is a critical 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 leak the decoded arguments of a tagged value when its THAW method dies in decode_tag.
With allow_tags, a tagged value's class name and argument array are decoded and passed to the class's THAW method. Both are released only after THAW returns, so a THAW that dies leaves the whole decoded argument structure allocated.
Each rejected document leaks data of a size the sender chooses, so a process that catches the error and keeps running exhausts its memory.
Weakness: CWE-401
Which versions are affected by CVE-2026-110685?
How do I fix CVE-2026-110685?
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-2026-110685 being exploited?
There is no known exploitation of CVE-2026-110685 in the wild and no public exploit code.
Sources
Also known as AZL-109851, DEBIAN-CVE-2026-110685, GHSA-mv2h-wx54-jcf9, UBUNTU-CVE-2026-110685.