Type confusion in Cpanel::JSON::XS for Perl decoding duplicate keys
Key facts
- Attack vector
- Network
- Privileges required
- Low
- 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-843 and the CVSS impact.
Summary
Cpanel::JSON::XS for Perl from 4.33 before 4.80 fails to detect repeated non-ASCII bare keys, so a repeated key can replace an earlier value. When decoded with relaxed and dupkeys_as_arrayref, a repeated bare key replaces the array that collects a key's values with a plain value, which is then used as an array (CWE-843). A remote attacker with low privileges who supplies untrusted JSON can crash the process or dereference an address chosen by a JSON number.
Written with Claude Haiku 5.5 from the sources below · 2026-10-29
Description from the CNA
Cpanel::JSON::XS versions from 4.33 before 4.80 for Perl miss duplicate non-ASCII bare keys, allowing type confusion under dupkeys_as_arrayref in decode_hv. With allow_barekey, which relaxed enables, a bare key containing a non-ASCII byte is stored as UTF-8 but looked up as raw bytes, so a repeated key escapes the duplicate-key check and replaces the earlier value. From 4.41, under dupkeys_as_arrayref, a bare repeat replaces the array that collects a key's values with a plain value, and the next quoted repeat pushes onto that value as if it were an array. A JSON integer there is dereferenced as a pointer. Untrusted JSON decoded with relaxed and dupkeys_as_arrayref can crash the process or dereference an address chosen by a JSON number.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | Cpanel-JSON-XS | 4.33 to before 4.80 | 4.80 | Patch available | CNA |
- Cpanel-JSON-XS Vendor— Affected 4.33 to before 4.80 Fixed in 4.80 Patch available CNA
Remediation
Upgrade Cpanel-JSON-XS to version 4.80, the fixed version for affected versions from 4.33 before 4.80.
Written with Claude Haiku 5.5 from the sources below · 2026-10-29
- Fix · CNA Cpanel-JSON-XS Fixed in 4.80
Vendor assessments
Timeline
- 2026-10-20 Threatist record created from CVE-2026-110674
- 2026-10-20 Alias added: GHSA-c92x-ph36-v6p2
- 2026-10-20 Affected versions changed · Red Hat
- 2026-10-20 CVSS score added · Red Hat
- 2026-10-21 CVSS score changed · Red Hat
- 2026-10-29 CVSS score added · CISA ADP
- 2026-10-29 CISA SSVC decision points changed
References
Sources
- CVE-2026-110674 · CVE Program
- CVE-2026-110674 · NVD
- FIRST EPSS
- GHSA-c92x-ph36-v6p2 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-110674 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences