CVE-2026-65067
Received Received - Intake

Insecure File Creation in Data::Intern::Shared Perl Module

Publication date: 2026-07-21

Last updated on: 2026-07-21

Assigner: CPANSec

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.

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Meta Information

Published
2026-07-21
Last Modified
2026-07-21
Generated
2026-07-22
AI Q&A
2026-07-21
EPSS Evaluated
N/A
NVD
CVE-2026-65067
EUVD
EUVD-2026-46380

Affected Vendors & Products

Currently, no data is known.

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-732 The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.
CWE-59 The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

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Executive Summary

This vulnerability affects the Perl module Data::Intern::Shared before version 0.02. It creates a shared memory file in a directory like /tmp or /dev/shm that is readable by any user on the system. The file is created with weak permissions (0644) and lacks protections like O_EXCL or O_NOFOLLOW, allowing attackers to manipulate it via symlinks or race conditions.

Detection Guidance

Check for world-readable files in shared directories like /tmp or /dev/shm. Look for files with mode 0644 created by Data::Intern::Shared. Use commands like 'find /tmp -type f -perm 0644 -ls' or 'ls -la /dev/shm' to inspect permissions.

Impact Analysis

An attacker could read sensitive data stored in the shared memory segment, such as IPC payloads. They might also exploit race conditions or symlink attacks to redirect the file to unintended locations, potentially leading to unauthorized access or data leakage.

Compliance Impact

This vulnerability could lead to unauthorized data exposure, violating confidentiality requirements in GDPR and HIPAA. It may result in non-compliance due to insufficient access controls and shared memory protections.

Mitigation Strategies

Update Data::Intern::Shared to version 0.02 or later. Remove any existing shared files created by the vulnerable version. Set stricter permissions on shared directories like /tmp and /dev/shm.

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