The vulnerability in Data::PubSub::Shared (prior to version 0.07) involves the creation of a mmap backing file with mode 0666, which under default umask results in a world-readable file (0644). The file is opened without the O_EXCL or O_NOFOLLOW flags, allowing an attacker to exploit symlink following and pre-creation race conditions. Since the shared segment resides in directories accessible by local users (e.g., /tmp or /dev/shm), any local user can read IPC payloads and potentially manipulate the file open operation to redirect or replace the file, leading to information disclosure.

Local attackers can read sensitive inter-process communication data due to world-readable file permissions. The absence of O_NOFOLLOW and O_EXCL flags enables symlink attacks and pre-creation race conditions, increasing the risk of unauthorized data access or manipulation. The vulnerability does not affect integrity or availability but compromises confidentiality of IPC payloads.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict local user access to the shared directories (e.g., /tmp, /dev/shm) used by Data::PubSub::Shared to limit exposure. Avoid running the vulnerable versions in multi-user environments where untrusted local users have access. Monitor vendor channels for updates or patches addressing this issue.