CVE-2026-110688

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

Published Oct 19, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
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.

Remediation

Vendor Solution

Upgrade to Cpanel-JSON-XS 4.80 or later.

Tracking

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Advisories

No advisories available
History
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'}

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

Sources

Status
PUBLISHED
Assigner
CPANSec
Published
Updated
Oct 29, 2026, 5:18 PM
Reserved
Oct 14, 2026, 1:27 PM
Status
Awaiting Analysis
Published
Oct 19, 2026, 7:17 PM
Modified
Oct 29, 2026, 6:17 PM