Vulnerability · Published Jul 21, 2026 · Assigned by CPANSec
CVE-2026-64613Data::Buffer::Shared versions before 0.05 for Perl create a world-readable mmap backing file and open it without O_NOFOLLOW
Medium 6.2
In plain English
A medium-severity incorrect permission assignment in Data::Buffer::Shared from EGOR. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 7% of all known vulnerabilities).
Official description
Data::Buffer::Shared versions before 0.05 for Perl create a world-readable mmap backing file and open it without O_NOFOLLOW. The segment is created in buf_generic.h with open(path, O_RDWR|O_CREAT|O_EXCL, 0666). O_EXCL blocks a pre-seeded file on create, but the mode is 0666, so under the default umask 022 the file is created mode 0644 (world-readable), and O_NOFOLLOW is absent, so a symlink planted at the path is followed when the segment is attached. A "Shared" segment naturally lives in a shared directory such as /tmp or /dev/shm, where any local user can read the IPC payloads stored in the world-readable segment, and a pre-planted symlink at the path redirects the open to another file.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| EGOR | Data::Buffer::Shared | 0 – before 0.05 |
Weakness: CWE-732, CWE-59 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N