# 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.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Oct 2026
- **Updated:** 29 Oct 2026
- **Also known as:** AZL-109860, DEBIAN-CVE-2026-110686, GHSA-q5qq-6rc9-83rg, UBUNTU-CVE-2026-110686

## 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 (Use After Free)

## Which versions are affected by CVE-2026-110686?


## How do I fix CVE-2026-110686?

Upgrade to a fixed version.

## Is CVE-2026-110686 being exploited?

There is no known exploitation of CVE-2026-110686 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-110686 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-110686 in the wild and no public exploit code.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-110686/ (Markdown: https://insights.sbomify.com/CVE-2026-110686/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-110686
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-110686
- OSV: https://osv.dev/vulnerability/CVE-2026-110686

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-110686/
Summaries are generated and may contain mistakes; the official description above is the record.