# CVE-2026-110676: libcpanel-json-xs-perl: Cpanel::JSON::XS versions before 4.80 for Perl allow memory exhaustion by encoding exponent notation as full decimal...

CVE-2026-110676 is fixed in 4 products on 1 platform, first by DEBIAN-CVE-2026-110676, released October 24, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-110676
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0049
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 15, 2026

## Description

Cpanel::JSON::XS versions before 4.80 for Perl allow memory exhaustion by encoding exponent notation as full decimal digits under allow_bignum.  With allow_bignum, a JSON number with a fraction or exponent decodes to a Math::BigFloat, which stores the exponent separately and so decodes cheaply. Encoding it untyped or as JSON_TYPE_FLOAT writes the plain decimal form with one digit per unit of exponent. Nothing bounds the exponent, so the 12-byte text [1e30000000] encodes to 30 MB.  Untrusted JSON decoded with allow_bignum and encoded again can exhaust memory and CPU.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libcpanel-json-xs-perl Debian 14 | 4.80-1 | [DEBIAN-CVE-2026-110676](https://patchblox.com/security/data/fix/linux/debian-cve-2026-110676.md) | Oct 24, 2026 |
| Linux | perl-Cpanel-JSON-XS Fedora 43 | 4.80-1.fc43 | [FEDORA-2026-4447E52D23](https://patchblox.com/security/data/fix/linux/fedora-2026-4447e52d23.md) | Nov 7, 2026 |
| Linux | perl-Cpanel-JSON-XS amzn 2023 | 4.25-2.amzn2023.0.10 | [ALAS2023-2026-3352](https://patchblox.com/security/data/fix/linux/alas2023-2026-3352.md) | Nov 7, 2026 |
| Linux | perl-Cpanel-JSON-XS opensuse-leap 16.0 | 4.800.0-bp160.1.1 | [OPENSUSE-SU-2026:22187-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22187-1.md) | Nov 7, 2026 |
| Linux | perl-Cpanel-JSON-XS sles 15.7 | 4.800.0-150700.3.9.1 | [SUSE-SU-2026:4926-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-4926-1.md) | Nov 7, 2026 |
| Linux | perl-Cpanel-JSON-XS-debuginfo Fedora 43 | 4.80-1.fc43 | [FEDORA-2026-4447E52D23](https://patchblox.com/security/data/fix/linux/fedora-2026-4447e52d23.md) | Nov 7, 2026 |
| Linux | perl-Cpanel-JSON-XS-debuginfo amzn 2023 | 4.25-2.amzn2023.0.10 | [ALAS2023-2026-3352](https://patchblox.com/security/data/fix/linux/alas2023-2026-3352.md) | Nov 7, 2026 |
| Linux | perl-Cpanel-JSON-XS-debugsource Fedora 43 | 4.80-1.fc43 | [FEDORA-2026-4447E52D23](https://patchblox.com/security/data/fix/linux/fedora-2026-4447e52d23.md) | Nov 7, 2026 |
| Linux | perl-Cpanel-JSON-XS-debugsource amzn 2023 | 4.25-2.amzn2023.0.10 | [ALAS2023-2026-3352](https://patchblox.com/security/data/fix/linux/alas2023-2026-3352.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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