# CVE-2026-12844: liblist-someutils-xs-perl: List::SomeUtils::XS versions before 0.59 for Perl have a heap buffer overflow in the pairwise function

CVE-2026-12844 is fixed in 4 products on 1 platform, first by DEBIAN-CVE-2026-12844, released June 26, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-12844
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0066
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 25, 2026

## Description

List::SomeUtils::XS versions before 0.59 for Perl have a heap buffer overflow in the pairwise function.  pairwise() collects the values returned by the block into a heap buffer sized to the longer input array, then grows the buffer before each copy with a single quadrupling (alloc <<= 2) instead of a loop. A block call that returns more than four times the current allocation in one invocation outgrows that one quadrupling, and the copy writes past the end of the buffer.  Any caller of pairwise() whose block returns, for a single pair, more than four times the longer input array's length writes past the buffer and corrupts the heap.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | liblist-someutils-xs-perl Debian 14 | 0.59-1 | [DEBIAN-CVE-2026-12844](https://patchblox.com/security/data/fix/linux/debian-cve-2026-12844.md) | Jun 26, 2026 |
| Linux | perl-List-SomeUtils-XS Fedora 43 | 0.59-1.fc43 | [FEDORA-2026-6217093B91](https://patchblox.com/security/data/fix/linux/fedora-2026-6217093b91.md) | Aug 10, 2026 |
| Linux | perl-List-SomeUtils-XS opensuse-leap 16.0 | 0.58-160000.3.2 | [OPENSUSE-SU-2026:21218-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21218-1.md) | Jul 6, 2026 |
| Linux | perl-List-SomeUtils-XS sles 15.6 | 0.56-150000.3.3.1 | [SUSE-SU-2026:2845-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2845-1.md) | Jul 10, 2026 |
| Linux | perl-List-SomeUtils-XS sles 15.7 | 0.56-150000.3.3.1 | [SUSE-SU-2026:2845-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2845-1.md) | Jul 10, 2026 |
| Linux | perl-List-SomeUtils-XS sles 16.0 | 0.58-160000.3.2 | [SUSE-SU-2026:22559-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22559-1.md) | Jul 6, 2026 |
| Linux | perl-List-SomeUtils-XS-debuginfo Fedora 43 | 0.59-1.fc43 | [FEDORA-2026-6217093B91](https://patchblox.com/security/data/fix/linux/fedora-2026-6217093b91.md) | Aug 10, 2026 |
| Linux | perl-List-SomeUtils-XS-debugsource Fedora 43 | 0.59-1.fc43 | [FEDORA-2026-6217093B91](https://patchblox.com/security/data/fix/linux/fedora-2026-6217093b91.md) | Aug 10, 2026 |

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Data as of 2026-11-08T13:06:02Z 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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