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CVE-2026-12844

HIGH

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…

Published
Jun 25, 2026
Updated
Jun 25, 2026
Affected
0 pkgs
Patched
None yet
Exploits
None indexed

EPSS Exploitation Probability

via FIRST.org ↗
0.4%probability of exploitation in next 30 days
Lower Risk34th percentile0.00%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

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.

Detection & mitigation playbook

Vulnerability

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Remediation status

    No patched version of the affected component has shipped for CVE-2026-12844 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

  3. Mitigate without a patch

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether CVE-2026-12844 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2026-12844. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

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
O3 Security · Impact-Aware SCA

Is CVE-2026-12844 in your dependencies?

O3 detects CVE-2026-12844 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works