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TI-2026-76558 Aliases CVE-2026-110677GHSA-mjfh-hmwc-q348

Memory leak in Cpanel::JSON::XS when decoding duplicate JSON keys

Priority LOW 39CWE-401Published · 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-401.

Summary

Cpanel::JSON::XS for Perl from 4.28 before 4.80 leaks memory in decode_hv when dupkeys_as_arrayref is set. The array collecting values of a duplicate object key is never released (CWE-401), and it also leaks when decoding fails after a duplicate key. An unauthenticated remote attacker can exhaust process memory by repeatedly decoding untrusted JSON that has a duplicate key with a large value.

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

Description from the CNA

Cpanel::JSON::XS versions from 4.28 before 4.80 for Perl leak the array collecting duplicate key values under dupkeys_as_arrayref in decode_hv. With dupkeys_as_arrayref, the values of a duplicate object key are collected into a new array. An extra reference is never released, so the array and every value in it outlive the decoded structure. The array also leaks when decoding fails after a duplicate key. Repeatedly decoding untrusted JSON with a duplicate key holding a large value exhausts process memory.

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-XS4.28 to before 4.804.80Patch availableCNA
  • Cpanel-JSON-XS Vendor— Affected 4.28 to before 4.80 Fixed in 4.80 Patch available CNA

Remediation

Upgrade Cpanel-JSON-XS to version 4.80, which fixes the flaw.

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-2026-110677
  2. 2026-10-20 Alias added: GHSA-mjfh-hmwc-q348
  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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