Description
Data::Intern::Shared versions before 0.02 for Perl create a world-readable mmap backing file and open it without O_EXCL or O_NOFOLLOW. The segment is created in intern.h with open(path, O_RDWR|O_CREAT, 0666). The mode is 0666, so under the default umask 022 the file is created mode 0644 (world-readable). O_NOFOLLOW is absent, so a symlink planted at the path is followed, and O_EXCL is absent, so the open silently uses a pre-planted file instead of failing. 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 file or symlink at the path lets a local attacker win a pre-creation race or redirect the open.
References2
Metrics
- CVSS 3.1
-
3.8
LOW
Score source: CNA
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N - EPSS — exploit probability
- 0% percentile: 4 · as of 14 November 2026
- CWE
- CWE-59CWE-732
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