---
id: "CVE-2026-110682"
kind: "vulnerability"
aliases: ["CVE-2026-110682"]
title: "Cpanel::JSON::XS: chunked input changes decoded top-level numbers in incr_parse"
severity: "low"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["cpanel-json-xs", "network-services", "package", "perl"]
not_affected_if: ["batch-decoding-only", "no-untrusted-streams"]
published_at: "2026-10-19T19:17:21+00:00"
first_seen_at: "2026-10-23T21:57:18+00:00"
updated_at: "2026-10-25T05:10:46+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-110682", "first_seen_at": "2026-10-23T21:57:18+00:00"}]
---

# Cpanel::JSON::XS: chunked input changes decoded top-level numbers in incr_parse

Cpanel::JSON::XS versions 4.42 through 4.79 for Perl decode a top-level number differently depending on how the input is split across reads, so the bytes 12 can become one value or two. A peer that controls read boundaries can change how many messages a stream consumer decodes and what values they carry.

_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'`
- Look for `incr_parse` calls on network or pipe input in the code base

## Fix

- Upgrade Cpanel::JSON::XS to `4.80` or later
- Until upgraded, avoid decoding bare top-level numbers from streams with `incr_parse`

## Timeline

- 2026-10-23T21:57:18+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-110682

## From the sources

Cpanel::JSON::XS versions from 4.42 before 4.80 for Perl let input chunking change the decoded value of top-level numbers in incr_parse.

allow_nonref is enabled by default and incr_parse inherits it. A top-level number, true, false or null has no closing delimiter, so the incremental parser decodes whatever has arrived. The bytes 12 decode as one value when read together, but as 1 and then 2 when split across two reads.

A peer that can influence read boundaries can change how many messages a stream consumer decodes and what values they carry.

---

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