CVE-2026-59146 in Data::SpatialHash::Shared
Summary
by MITRE • 07/21/2026
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.
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Analysis
by VulDB Data Team • 07/21/2026
The vulnerability in Data::SpatialHash::Shared versions prior to 0.02 represents a critical memory safety issue stemming from inadequate input validation within the spatial hash implementation. This Perl module manages spatial data structures that store and retrieve geometric objects efficiently, but the flawed validation mechanism creates opportunities for attackers to manipulate underlying memory through crafted file contents. The vulnerability manifests when the module processes files containing maliciously constructed bucket chains or free list indices, allowing for out-of-bounds memory access patterns that can lead to arbitrary code execution or system instability.
The technical flaw resides in the module's failure to validate array indices within critical functions sph_walk_cell and sph_alloc_slot despite having a validation function sph_validate_header that only examines header scalar values and region layout against file size. This validation gap creates an attack surface where attackers can manipulate the internal data structures without triggering any validation errors, as the header validation remains successful even when array contents are corrupted. The sph_walk_cell function directly accesses buckets[b] and follows next links without bounds checking, while sph_alloc_slot writes to free_head indices stored in the file without validating their relationship to maximum entry counts.
This vulnerability enables a local privilege escalation scenario where an attacker with write access to the backing file can corrupt memory structures through carefully crafted modifications to bucket chains or free lists. The out-of-bounds reads occur when the module follows bucket chain pointers that reference memory locations beyond the allocated array bounds, potentially leading to information disclosure or crashes. Similarly, out-of-bounds writes happen when allocation operations modify free-list head indices that point outside the valid range of available entries, causing memory corruption that may result in denial of service or arbitrary code execution. This type of vulnerability falls under CWE-129 Input Validation and Output Encoding, specifically addressing insufficient validation of array indices.
The operational impact extends beyond simple crashes to potential information disclosure through memory reads and system compromise through memory corruption techniques. Attackers can exploit this vulnerability by creating malicious files that appear valid to the header validator but contain corrupted internal structures, allowing them to manipulate process memory in ways that could lead to privilege escalation or persistent access to affected systems. The attack requires local file write access, making it particularly concerning for applications that process untrusted spatial data from external sources or where multiple users have write permissions to shared storage locations.
Mitigation strategies should focus on implementing comprehensive input validation that bounds all array accesses within the spatial hash data structures, including validation of bucket chain pointers and free-list indices against maximum entry counts. The module should validate internal array contents during header validation rather than relying solely on header scalar values, ensuring that all indices reference valid memory locations before any operations are performed. Additionally, implementing proper bounds checking in sph_walk_cell and sph_alloc_slot functions would prevent out-of-bounds access patterns while maintaining the module's core functionality. This vulnerability aligns with ATT&CK technique T1059 Command and Scripting Interpreter and T1210 Exploitation of Remote Services, as it represents a local code execution vulnerability that can be leveraged for system compromise through file-based attacks.