CVE-2026-59142
CRITICALData::HashMap::Shared versions before 0.14 for Perl allow an out-of-bounds read via an unvalidated arena offset and length in shm_str_copy. The attach-time validator shm_validate_header…
Description
Data::HashMap::Shared versions before 0.14 for Perl allow an out-of-bounds read via an unvalidated arena offset and length in shm_str_copy.
The attach-time validator shm_validate_header checks the header scalars and region layout against the file size, but does not validate the array contents it then trusts. shm_str_copy does memcpy(dst, arena + off, len) with off and len read raw from the mmap'd segment and unbounded, on the each, keys, values, pop, shift, take, swap, drain and cursor paths. The get path bounds off and len separately and is not affected.
A local peer that can write the backing file can leave the header valid while poisoning a record's offset and length, so iterating or draining the map copies a file-controlled offset and length out of the arena, reading adjacent memory or crashing the process.
Detection & mitigation playbook
VulnerabilityDetect
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.
Remediation status
No patched version of the affected component has shipped for CVE-2026-59142 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
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.
How O3 protects you
O3 pinpoints whether CVE-2026-59142 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-2026-59142. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-59142 in your dependencies?
O3 detects CVE-2026-59142 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.