# CVE-2026-14803: libmojolicious-perl: Mojo::JSON versions before 9.47 for Perl allow memory exhaustion via unbounded recursion in the pure-Perl decoder

CVE-2026-14803 is fixed in 3 products on 1 platform, first by DEBIAN-CVE-2026-14803, released July 9, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-14803
- Priority: Routine
- CVSS: 6.5 (medium)
- EPSS: 0.0053
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 6, 2026

## Description

Mojo::JSON versions before 9.47 for Perl allow memory exhaustion via unbounded recursion in the pure-Perl decoder.  The pure-Perl decode path (`_decode_value` dispatching to `_decode_array` and `_decode_object`) recurses with no depth limit, so a small deeply nested JSON document can consume excessive memory.  This path is the default when Cpanel::JSON::XS is not installed or `MOJO_NO_JSON_XS=1` is set; the Cpanel::JSON::XS fast path is not affected.  Any caller that decodes an untrusted JSON body, for example `Mojo::Message::json` reached through `$c->req->json`, can exhaust process memory and cause denial of service.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libmojolicious-perl Debian 14 | 9.47+dfsg-1 | [DEBIAN-CVE-2026-14803](https://patchblox.com/security/data/fix/linux/debian-cve-2026-14803.md) | Jul 9, 2026 |
| Linux | perl-Mojolicious amzn 2023 | 9.48-2.amzn2023.0.1 | [ALAS2023-2026-3209](https://patchblox.com/security/data/fix/linux/alas2023-2026-3209.md) | Nov 7, 2026 |
| Linux | perl-Test-Mojo amzn 2023 | 9.48-2.amzn2023.0.1 | [ALAS2023-2026-3209](https://patchblox.com/security/data/fix/linux/alas2023-2026-3209.md) | Nov 7, 2026 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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