The vulnerability in Data::Graph::Shared (versions <0.04) arises from the creation of a mmap backing file with overly permissive file mode (0666) and the lack of O_NOFOLLOW and O_EXCL flags during file open operations. This leads to a world-readable file that can be accessed by any local user. Additionally, the absence of O_NOFOLLOW allows symlink following, and the absence of O_EXCL permits silent use of pre-existing files, enabling local attackers to perform pre-creation race attacks or redirect file opens to attacker-controlled files. This insecure permission assignment and unsafe file handling violate secure IPC practices and expose sensitive IPC payloads to unauthorized local users.

Local users on the system can read the memory-mapped IPC payloads stored in the world-readable backing file. They can also exploit the lack of O_NOFOLLOW and O_EXCL to redirect file opens via symlinks or pre-created files, potentially leading to unauthorized data disclosure or manipulation of IPC resources. This compromises the confidentiality and integrity of inter-process communication data managed by Data::Graph::Shared.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, users should avoid running Data::Graph::Shared versions prior to 0.04 in multi-user environments or restrict access to shared directories like /tmp or /dev/shm. Applying stricter filesystem permissions and monitoring for suspicious symlinks may reduce risk but do not fully mitigate the vulnerability.