Description
Cpanel::JSON::XS versions from 4.51 before 4.80 for Perl allow quadratic CPU use by revalidating the remaining buffer per value in incr_parse.

At the first non-ASCII byte in a string, the decoder validates UTF-8 from there to the end of its input. incr_parse decodes each buffered value with a fresh decoder, so every value revalidates the rest of the buffer, and doubling the input quadruples the work.

A peer that sends about a megabyte of ordinary non-ASCII JSON in one read ties up the process for seconds of CPU time.
Published: 2026-10-19
Score: 7.5 High
EPSS: < 1% Very Low
KEV: No
AI Analysis

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Remediation

Vendor Solution

Upgrade to Cpanel-JSON-XS 4.80 or later.

Tracking

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Advisories

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History

Thu, 29 Oct 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 19 Oct 2026 21:00:00 +0000

Type Values Removed Values Added
First Time appeared Rurban
Rurban cpanel::json::xs
Vendors & Products Rurban
Rurban cpanel::json::xs

Mon, 19 Oct 2026 18:30:00 +0000

Type Values Removed Values Added
Description Cpanel::JSON::XS versions from 4.51 before 4.80 for Perl allow quadratic CPU use by revalidating the remaining buffer per value in incr_parse. At the first non-ASCII byte in a string, the decoder validates UTF-8 from there to the end of its input. incr_parse decodes each buffered value with a fresh decoder, so every value revalidates the rest of the buffer, and doubling the input quadruples the work. A peer that sends about a megabyte of ordinary non-ASCII JSON in one read ties up the process for seconds of CPU time.
Title Cpanel::JSON::XS versions from 4.51 before 4.80 for Perl allow quadratic CPU use by revalidating the remaining buffer per value in incr_parse
Weaknesses CWE-407
References

Subscriptions

Rurban Cpanel::json::xs
cve-icon MITRE

Status: PUBLISHED

Assigner: CPANSec

Published:

Updated: 2026-10-29T17:18:17.844Z

Reserved: 2026-10-14T13:27:36.845Z

Link: CVE-2026-110688

cve-icon Vulnrichment

Updated: 2026-10-29T17:17:48.243Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-19T19:17:22.420

Modified: 2026-10-29T18:17:22.727

Link: CVE-2026-110688

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-29T21:45:15Z

Weaknesses