CVE-2026-59140
Data::SortedSet::Shared versions before 0.03 for Perl allow an out-of-bounds read via unvalidated node indices in the rank and min/max query paths. The attach-time validator ss_validate_header bounds only the root index against the node pool (node_capacity). The order-statistics and min/max queries then follow children[], leftmost and rightmost node indices read raw from the mmap'd segment without bounding them against node_capacity. A full structural check (ss_validate_tree) exists but runs only via an explicit validate method, not on attach. A local peer that can write the backing file can leave the header valid while poisoning the tree links, so the next rank, min or max query dereferences an out-of-bounds node index, reading adjacent memory or crashing the process.
No public exploitation has been reported so far. No distribution fix is listed yet; apply vendor mitigations and monitor.
Recommended action: Track your distribution's security tracker and apply the fix as soon as it ships.
Severity metrics
CVSS 3.1 : 9.1 CRITICAL
Vector: AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Affected & fixed versions by distribution
Versions are the native distribution strings (backport-aware): RHEL/Debian/SUSE backport fixes, so compare with the distro version comparator (dpkg / rpm / vercmp), not the upstream version.
No affected package in the tracked watchlist yet (Debian, Ubuntu, Arch, SUSE, Red Hat...). Triage may still be pending.