# CVE-2026-110687: Cpanel::JSON::XS versions from 4.43 before 4.80 for Perl misorder byte-string keys during canonical encoding in utf16_cmp.

> An attacker can cause inconsistent canonical JSON encoding by exploiting key sorting flaws, leading to data integrity issues in applications using the library.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **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:** DEBIAN-CVE-2026-110687, GHSA-fq4p-2pcg-jg87, UBUNTU-CVE-2026-110687

## What is CVE-2026-110687?

CVE-2026-110687 is a high-severity 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 4.43 before 4.80 for Perl misorder byte-string keys during canonical encoding in utf16_cmp.

canonical sorts keys by UTF-16 code units. When any key in a hash is UTF-8 flagged, every key is decoded as UTF-8 for the comparison, including byte-string keys that the encoder writes out as Latin-1 characters. A byte-string key whose bytes are valid UTF-8 is sorted out of order, and two keys that encode differently can compare equal and are left in hash order.

The same data can encode to different canonical documents across processes.

Weakness: CWE-176 (Improper Handling of Unicode Encoding)

## Which versions are affected by CVE-2026-110687?


## How do I fix CVE-2026-110687?

Upgrade to a fixed version.

## Is CVE-2026-110687 being exploited?

There is no known exploitation of CVE-2026-110687 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-110687 and fix it if it is affected.

What it is: CVE-2026-110687 is a high-severity 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-2026-110687 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-2026-110687/ (Markdown: https://insights.sbomify.com/CVE-2026-110687/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-110687
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-110687
- OSV: https://osv.dev/vulnerability/CVE-2026-110687

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-110687/
Summaries are generated and may contain mistakes; the official description above is the record.