CVE-2026-110686 Cpanel::JSON::XS versions before 4.80 for Perl use freed filter callbacks when a filter removes itself during decoding in decode_hv.
A use-after-free vulnerability in the Cpanel::JSON::XS Perl library allows attackers to cause a denial of service via crafted JSON input.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-110686?
CVE-2026-110686 is a medium-severity use after free 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 use freed filter callbacks when a filter removes itself during decoding in decode_hv.
A decode copies the parser's filter_json_object and filter_json_single_key_object callbacks without taking references to them. A filter callback that removes the last single-key filter frees the callback table while the decode in progress still uses it. The next object is dispatched through freed memory and can crash the process.
Weakness: CWE-416
Which versions are affected by CVE-2026-110686?
How do I fix CVE-2026-110686?
Upgrade to a fixed version.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-110686 being exploited?
There is no known exploitation of CVE-2026-110686 in the wild and no public exploit code.
Sources
Also known as AZL-109860, DEBIAN-CVE-2026-110686, GHSA-q5qq-6rc9-83rg, UBUNTU-CVE-2026-110686.