cPanel CVE-2026-110681
CVE-2026-110681 is one of a coordinated set of fixes in Cpanel::JSON::XS for Perl: versions before 4.80 — use the parent interpreter's scalars from a parser object cloned into a new ithread. The corrected build is Cpanel::JSON::XS 4.80, delivered to cPanel & WHM servers through the standard update channel.
What this means under a SharedLicense license
Parsing untrusted JSON with the affected Cpanel::JSON::XS builds is the exposure: CWE-416 in the advisory's own data, CVSS 8.1 — practical risk ranges from resource exhaustion to memory corruption.
Cpanel::JSON::XS versions before 4.80 for Perl use the parent interpreter’s scalars from a parser object cloned into a new ithread.
A parser object holds its callbacks and its incremental parse buffer as raw scalar pointers. When a thread is created, these are copied into the new interpreter unchanged, so the child’s parser uses, and later frees, scalars that belong to the parent and may already have been freed there.
A parser created before a thread starts and used inside it can call freed callbacks, corrupt reference counts and crash the process.
Reference: https://nvd.nist.gov/vuln/detail/CVE-2026-110681
Frequently Asked Questions
What is CVE-2026-110681?
What version fixes it?
Do I have to do anything on a managed cPanel server?
References
Check your system for vulnerabilities
Select your product and operating system to see the exact fix commands that apply to you.
Check Your System