---
id: "CVE-2026-110675"
kind: "vulnerability"
aliases: ["CVE-2026-110675"]
title: "Cpanel::JSON::XS: malformed UTF-8 accepted in bare hash keys"
severity: "low"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["cpan", "package", "perl"]
not_affected_if: ["auth-required", "default-config"]
published_at: "2026-10-19T19:17:21+00:00"
first_seen_at: "2026-10-23T21:57:18+00:00"
updated_at: "2026-10-25T05:10:52+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-110675", "first_seen_at": "2026-10-23T21:57:18+00:00"}]
---

# Cpanel::JSON::XS: malformed UTF-8 accepted in bare hash keys

Cpanel::JSON::XS versions from 4.33 before 4.80 accept malformed UTF-8, control bytes and backslashes in unquoted (bare) hash keys when decoding with utf8 and allow_barekey enabled. Quoted keys and values are still validated, and the bad keys later cause errors when the hash is processed with lc, uc or re-encoded.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed version with `perl -MCpanel::JSON::XS -e 'print $Cpanel::JSON::XS::VERSION'`
- Search code for `allow_barekey` together with `utf8` in decode calls to find exposed decoders
- Check whether JSON from untrusted input is decoded with these options

## Fix

- Upgrade Cpanel::JSON::XS to `4.80` or later
- Or disable `allow_barekey` where untrusted JSON is decoded

## Timeline

- 2026-10-23T21:57:18+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-110675

## From the sources

Cpanel::JSON::XS versions from 4.33 before 4.80 for Perl accept malformed UTF-8 in bare hash keys under allow_barekey in decode_hv.

With utf8 and allow_barekey, which relaxed enables, a quoted key is validated as UTF-8 but a bare key's bytes are stored as a UTF-8 flagged string without any check. Malformed UTF-8, control bytes and backslashes reach the decoded hash, while malformed UTF-8 and control bytes in a quoted key or a value are rejected.

Later operations on the key, including lc, uc or encoding the hash again, die with a malformed UTF-8 error.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_