Data::RingBuffer::Shared prior to 0.04 creates a shared memory segment backed by a file that is world‑readable because it is opened with mode 0666 and neither O_EXCL nor O_NOFOLLOW. A local user can read the contents of another user’s shared buffer and, if a symlink is planted at the creation path, can redirect the open to a file of the attacker’s choosing, allowing potential data leakage or tampering. The consequence is the disclosure of sensitive inter‑process data to local users on the same host.

This issue affects the Perl module Data::RingBuffer::Shared supplied by EGOR. All versions earlier the module creates a backing file in a shared directory such as /tmp or /dev/shm, which standard installation paths expose to all local users.

The CVSS score of 3.8 indicates moderate severity, while the EPSS score of less than 1% suggests that current exploit prevalence is low. The vulnerability is not listed in the CISA KEV catalog. The attack vector is local; a user with write access to the shared directory can create a symlink or pre‑plant a file, then instantiate the shared buffer to read or corrupt another user’s data. Because the attack requires local file system access and is discoverable only on systems that use this specific module, widespread automated exploitation is unlikely, but the impact to confidentiality is real if the data in the buffer is sensitive.