CVE-2026-59146: Data::SpatialHash::Shared versions before 0.02 for Perl allow out-of-bounds reads and writes via unvalidated bucket, link and free-list indices in sph_walk

Data::SpatialHash::Shared versions before 0.02 for Perl allow out-of-bounds reads and writes via unvalidated bucket, link and free-list indices in sph_walk_cell

Data::SpatialHash::Shared versions before 0.02 for Perl allow out-of-bounds reads and writes via unvalidated bucket, link and free-list indices in sph_walk_cell and sph_alloc_slot. The attach-time validator sph_validate_header checks the header scalars and region layout against the file size, but does not validate the array contents it then trusts. sph_walk_cell reads entries[buckets[b]] and follows each entry's next link raw, and sph_alloc_slot writes through a file-stored free_head index, none bounded against the entry count (max_entries). A local peer that can write the backing file can leave the header valid while poisoning the bucket chain and free list, so a query reads through an out-of-bounds bucket and next index and an insert writes through an out-of-bounds free-list head, corrupting memory or crashing the process.

Description from the National Vulnerability Database, published by 9b29abf9-4ab0-4765-b253-1875cd9b441e

What it means for a small business

If your business uses Data::SpatialHash::Shared, install the vendor's update. If you're not sure whether you use it, ask whoever manages your computers.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 0.17%, higher than 6% of CVEs. That’s low, but low isn’t zero, and the odds jump the day someone publishes an exploit. Scored October 29, 2026, updated daily.

Check your own setup

Website check: reads what your site runs from the outside (WordPress version, plugins it can see, old server software) and matches it against this database.
Server check: what your web server says about itself, and whether that version has known flaws.

Sources

Part of the Huttenlocher Technologies vulnerability database, refreshed twice a day from CISA and the NVD. The title, category and plain-language guidance are ours; check the linked record before acting on a detail. This is general guidance, not a review of your systems.

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