Authenticated object injection via unrestricted PHP deserialization
Published Sep 15, 2026 · Updated Sep 15, 2026
PHP object injection in Cotonti Comments plugin 1.0.0 allows remote authenticated users to alter database data through crafted POST input. CreateAction.php passes the base64-decoded ci value to unserialize() without restricting instantiable classes, enabling attacker-controlled properties and gadget execution. Comment-write access is required; the demonstrated MySQL_cache destructor chain inserts attacker-chosen cache rows, while code execution depends on another loaded gadget chain.
Summary
What happened
PHP object injection in Cotonti Comments plugin 1.0.0 allows remote authenticated users to alter database data through crafted POST input. CreateAction.php passes the base64-decoded ci value to unserialize() without restricting instantiable classes, enabling attacker-controlled properties and gadget execution. Comment-write access is required; the demonstrated MySQL_cache destructor chain inserts attacker-chosen cache rows, while code execution depends on another loaded gadget chain.
The record
- CVE
- CVE-2026-91939
- Published
- Sep 15, 2026
- Updated
- Sep 15, 2026
- Vendor
- Cotonti
- Product
- Cotonti
- Classifications
- CWE-502, T1190
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 15, 2026CVE publishedPublication date reported by the CVE source.
- Sep 15, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=1.0.0 <=1.0.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- cotonti-commentswidget-pocproof of concept · unverified
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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