CVE-2026-71294

Received Received - Intake

PHP Object Injection in Cotonti CMS Comments Plugin

Publication date: 2026-08-05

Last updated on: 2026-08-10

Assigner: 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c

Description

Cotonti CMS's Comments plugin deserializes user-supplied data without restricting the classes that may be instantiated. In plugins/comments/controllers/actions/CreateAction.php, a POST parameter obtained via (trim-only sanitization) is passed to with no restriction, reachable by any member with write access to comments (the default setting in plugins/comments/comments.setup.php).

CVSS Scores

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Meta Information

Published

2026-08-05

Last Modified

2026-08-10

Generated

2026-08-16

AI Q&A

2026-08-05

EPSS Evaluated

2026-08-15

NVD

CVE-2026-71294

EUVD

EUVD-2026-53379

Affected Vendors & Products

Vendor	Product	Version / Range
cotonti	cms	*
cotonti	cotonti	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-502	The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

Attack-Flow Graph

Executive Summary

Cotonti CMS's Comments plugin improperly deserializes user input without restricting which classes can be instantiated. Attackers with write access to comments can exploit this by sending crafted serialized PHP objects, leading to potential object injection attacks.

Detection Guidance

Detecting this vulnerability requires checking for signs of PHP object injection attempts in Cotonti CMS logs or network traffic. Look for unusual base64-encoded POST parameters named 'ci' or 'cb' in comments-related requests. Inspect server logs for unserialize() calls without allowed_classes restrictions. No specific commands are provided in the context.

Impact Analysis

An attacker could execute arbitrary code, manipulate database entries, or perform unauthorized actions like deleting or modifying cached data. This could lead to data breaches, system compromise, or further exploitation depending on available gadget chains.

Compliance Impact

This vulnerability could lead to unauthorized data access or modification, violating GDPR's integrity and confidentiality requirements or HIPAA's safeguards for protected health information. Non-compliance risks include legal penalties and reputational damage.

Mitigation Strategies

Immediately update Cotonti CMS to the latest version that patches this issue. Disable write access to comments for non-trusted users by setting Auth_members to 'R' in plugins/comments/comments.setup.php. Disable the Comments plugin if not essential. Monitor for suspicious INSERT INTO cot_cache queries in database logs.

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