The vulnerability in Data::Intern::Shared (prior to version 0.02) arises from insufficient validation of slot, reverse, and arena indices used in the si_idx_find function. While the header and layout are validated at attach time, the arrays used for triple indirection reads are not checked for bounds. This allows a local attacker who can write to the backing file to poison these indices, causing out-of-bounds reads when functions like id_of, intern, or string are called. The string() function returns a length of bytes controlled by the attacker from the arena, potentially disclosing adjacent process memory. This is classified as a CWE-125 (Out-of-bounds Read) vulnerability. There is no CVSS score or known exploits in the wild, and no official remediation or patch is currently documented.

An attacker with local write access to the backing file can cause out-of-bounds reads in the affected library, potentially leading to disclosure of adjacent process memory. This could expose sensitive information from the process memory space. The vulnerability does not indicate remote exploitation or code execution capabilities based on the provided data.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict local write access to the backing file used by Data::Intern::Shared to trusted users only. Monitor for vendor updates regarding patches or official fixes.