CVE-2026-64617
Received Received - Intake

Information Disclosure in Data::PubSub::Shared Perl Module

Publication date: 2026-07-21

Last updated on: 2026-07-21

Assigner: CPANSec

Description
Data::PubSub::Shared versions before 0.07 for Perl create a world-readable mmap backing file and open it without O_EXCL or O_NOFOLLOW. The segment is created in pubsub.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-2026-64617
EUVD
EUVD-2026-46373

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.

Attack-Flow Graph

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Executive Summary

This vulnerability affects the Perl Data::PubSub::Shared module versions before 0.07. It creates a world-readable memory-mapped file without proper protections. The file is created with permissions 0644, making it readable by any user. Additionally, the code lacks O_EXCL and O_NOFOLLOW flags, allowing attackers to exploit symlink attacks or pre-race conditions to access sensitive IPC payloads stored in shared directories like /tmp or /dev/shm.

Detection Guidance

Check for world-readable mmap backing files in shared directories like /tmp or /dev/shm. Look for files with mode 0644 created by Data::PubSub::Shared versions before 0.07. Use commands like 'find /tmp -type f -perm 0644' to locate suspicious files.

Impact Analysis

An attacker could read sensitive data stored in the shared memory segment, including IPC payloads. Since the file is world-readable, any local user can access this data. If combined with symlink or race condition attacks, an attacker might redirect the open call to a different file, potentially leading to unauthorized access or data leakage.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, violating confidentiality requirements in GDPR and HIPAA. GDPR requires protection of personal data, while HIPAA mandates safeguards for protected health information. A breach due to this flaw may result in non-compliance, legal penalties, and reputational damage.

Mitigation Strategies

Upgrade Data::PubSub::Shared to version 0.07 or later. Ensure shared directories like /tmp or /dev/shm have restrictive permissions (e.g., 0700). Avoid using world-writable directories for sensitive IPC operations.

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