Data::RingBuffer::Shared before 0.04 contains a flaw where the ring_read_seq routine copies an unvalidated element size directly into a fixed 8‑byte buffer on the stack. When the elem_size field in the shared memory header exceeds eight bytes, a memcpy writes beyond the bounds of the destination scalar, corrupting adjacent stack data. This classic stack buffer overflow can compromise program stability and potentially enable arbitrary code execution.

The vulnerability afflicts the EGOR Data::RingBuffer::Shared Perl module. All releases earlier than 0.04 are vulnerable. No other vendors or products are listed.

The CVSS score of 9.8 reflects critical severity, while the EPSS score of less than 1% indicates a low current exploitation probability. The flaw is not listed in CISA KEV. The attack requires a local attacker who can write to the backing file used by the shared buffer. If the backing file resides in a directory writable by untrusted local users or processes, an attacker can set an oversized elem_size, trigger the overflow, and corrupt the stack. The description does not confirm successful code execution, but based on the nature of the overflow it is inferred that an attacker could potentially leverage the memory corruption for code execution.