# 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.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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-109851, DEBIAN-CVE-2026-110685, GHSA-mv2h-wx54-jcf9, UBUNTU-CVE-2026-110685

## 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 (Missing Release of Memory after Effective Lifetime)

## Which versions are affected by CVE-2026-110685?


## How do I fix CVE-2026-110685?

Upgrade to a fixed version.

## Is CVE-2026-110685 being exploited?

There is no known exploitation of CVE-2026-110685 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-110685 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-110685 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-2026-110685/ (Markdown: https://insights.sbomify.com/CVE-2026-110685/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-110685
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-110685
- OSV: https://osv.dev/vulnerability/CVE-2026-110685

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-110685/
Summaries are generated and may contain mistakes; the official description above is the record.