CVE-2026-64613
MEDIUM
MEDIUM
Priority: 0.01
BB Relevance:
47/100
Published: 2026-07-21
Modified: 2026-10-24
First seen: 2026-10-29
Status: active
Attack Surface
Low Complexity
No Auth
No Interaction
Conf. Impact
CVSS Vector Breakdown
AV:
Local
AC:
Low
PR:
None
UI:
None
S:
Unchanged
C:
High
I:
None
A:
None
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.