# CVE-2026-85644: libxs-parse-keyword-perl: XS::Parse::Infix versions from 0.40 through 0.49 for Perl treat a number as an array reference

CVE-2026-85644 is fixed in 2 products on 1 platform, first by libxs-parse-keyword-perl 0.49-1ubuntu0.1, released September 28, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-85644
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0037
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 28, 2026

## Description

XS::Parse::Infix versions from 0.40 through 0.49 for Perl treat a number as an array reference.  The wrapper function XS::Parse::Infix generates for a list-associative infix operator checks whether arguments are array references, but it tests using SvRV() rather than SvROK(). SvRV() reads a union slot that only holds a referent once SvROK(sv) is true, so the guard never validates that it is a reference. For an IV or NV that slot holds the number itself, SvRV() returns the caller's value and SvTYPE() dereferences it at offset 12. This will generally result in a segmentation fault.  An application that hands the wrapper a list built from decoded input (for example, from JSON) lets whoever supplies a number in that list choose the address that the interpreter dereferences.  An ordinary string's byte 12 is rarely SVt_PVAV so the guard croaks by luck, but an attacker-crafted string carrying 0x0b there passes, and the buffer is then used as an AV head, with AvARRAY taken from bytes 16-23 and its entries pushed onto the Perl stack as live SVs.  A simple proof-of-concept uses the zip operator:      use Syntax::Operator::Zip 'zip';      my @args = ([1], 2);     zip(@args);

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libxs-parse-keyword-perl Debian 14 | 0.51-1 | [DEBIAN-CVE-2026-85644](https://patchblox.com/security/data/fix/linux/debian-cve-2026-85644.md) | Oct 4, 2026 |
| Linux | libxs-parse-keyword-perl Ubuntu 26.04.1 LTS (resolute) | 0.49-1ubuntu0.1 | [libxs-parse-keyword-perl 0.49-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libxs-parse-keyword-perl-0.49-1ubuntu0.1.md) | Sep 28, 2026 |
| Linux | perl-XS-Parse-Keyword opensuse-leap 16.0 | 0.480.0-160000.3.1 | [OPENSUSE-SU-2026:22101-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-22101-1.md) | Nov 7, 2026 |
| Linux | perl-XS-Parse-Keyword sles 16.0 | 0.480.0-160000.3.1 | [SUSE-SU-2026:24244-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-24244-1.md) | Nov 7, 2026 |

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Data as of 2026-11-08T19:12:23Z 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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