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TI-2026-76567 Aliases CVE-2026-110688GHSA-cv8j-jrx6-q4fj

Cpanel::JSON::XS incr_parse quadratic CPU use on non-ASCII JSON

Priority LOW 39CWE-407Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-407.

Summary

Cpanel::JSON::XS versions from 4.51 before 4.80 for Perl allow quadratic CPU use because incr_parse revalidates the remaining buffer for every value. At the first non-ASCII byte in a string, the decoder validates UTF-8 from that point to the end of its input, and incr_parse decodes each buffered value with a fresh decoder, so doubling the input quadruples the work. A peer that sends about a megabyte of ordinary non-ASCII JSON in one read can tie up the process for seconds of CPU time. The weakness is CWE-407 (Inefficient Algorithmic Complexity), and the CVSS 3.1 base score is 7.5 (HIGH).

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00485 42nd percentileScored 2026-11-07
Fix Fixed Cpanel-JSON-XS: 4.80

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
—Cpanel-JSON-XS4.51 to before 4.804.80Patch availableCNA
  • Cpanel-JSON-XS Vendor— Affected 4.51 to before 4.80 Fixed in 4.80 Patch available CNA

Remediation

Upgrade Cpanel-JSON-XS to version 4.80 or later. Red Hat lists one product as not affected.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

  • Fix · CNA Cpanel-JSON-XS Fixed in 4.80

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-20 Threatist record created from CVE-2026-110688
  2. 2026-10-20 Alias added: GHSA-cv8j-jrx6-q4fj
  3. 2026-10-20 Affected versions changed · Red Hat
  4. 2026-10-20 CVSS score added · Red Hat
  5. 2026-10-21 CVSS score changed · Red Hat
  6. 2026-10-29 CVSS score added · CISA ADP
  7. 2026-10-29 CISA SSVC decision points changed

References

Patch 1

Other 1

Sources

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