Vulnerability · Published Jul 21, 2026 · Assigned by CPANSec
CVE-2026-59142Data::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
Critical 9.1
In plain English
A critical-severity out-of-bounds read in Data::HashMap::Shared from EGOR. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 46% of all known vulnerabilities).
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| EGOR | Data::HashMap::Shared | 0 – before 0.14 |
Weakness: CWE-125 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H