CVE-2026-110677 Cpanel::JSON::XS versions from 4.28 before 4.80 for Perl leak the array collecting duplicate key values under dupkeys_as_arrayref in decode_hv.
Attackers can exhaust process memory by repeatedly decoding untrusted JSON with duplicate keys when dupkeys_as_arrayref 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-2026-110677?
CVE-2026-110677 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 4.28 before 4.80 for Perl leak the array collecting duplicate key values under dupkeys_as_arrayref in decode_hv.
With dupkeys_as_arrayref, the values of a duplicate object key are collected into a new array. An extra reference is never released, so the array and every value in it outlive the decoded structure. The array also leaks when decoding fails after a duplicate key.
Repeatedly decoding untrusted JSON with a duplicate key holding a large value exhausts process memory.
Weakness: CWE-401
Which versions are affected by CVE-2026-110677?
How do I fix CVE-2026-110677?
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-2026-110677 being exploited?
There is no known exploitation of CVE-2026-110677 in the wild and no public exploit code.
Sources
Also known as AZL-109863, DEBIAN-CVE-2026-110677, GHSA-mjfh-hmwc-q348, UBUNTU-CVE-2026-110677.