Data::ReqRep::Shared versions prior to 0.05 create a mmap backing file with mode 0666 (resulting in 0644 after umask), making it world-readable. The file is opened without O_EXCL and O_NOFOLLOW flags, enabling an attacker to pre-create or symlink the file path to redirect the open call or win a race condition. Because the shared segment resides in commonly accessible directories, any local user can read IPC payloads, violating confidentiality and potentially enabling further local attacks. This vulnerability corresponds to CWE-732 (Incorrect Permission Assignment for Critical Resource) and CWE-59 (Improper Link Resolution).

Local users on the system can read sensitive inter-process communication data due to world-readable permissions on the mmap backing file. The absence of O_EXCL and O_NOFOLLOW flags allows attackers to exploit race conditions or symlink attacks to redirect or pre-create files, potentially leading to unauthorized data disclosure or manipulation of IPC mechanisms. This compromises confidentiality and integrity of IPC data within affected versions.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict local user access to shared directories such as /tmp or /dev/shm where the shared segment files reside, and monitor for suspicious symlink or file creation activity. Avoid running untrusted local code with permissions that allow access to these files. Follow vendor updates for official fixes or patches.