CVE-2026-93872: Cotonti 1.0.0 PHP Object Injection via Comments Plugin Edit Action cb Parameter

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-18 · updated 2026-09-22
Weakness: CWE-502

Description

Cotonti 1.0.0 passes the base64-decoded cb parameter to unserialize() without allowed_classes restriction in the comments plugin EditAction. Registered users with comment write permissions can instantiate arbitrary PHP objects and potentially achieve file write or code execution through gadget chains.

Affected products

Cotonti: from 1.0.0 through 1.0.0

References

https://github.com/Cotonti/Cotonti
https://github.com/Cotonti/Cotonti/blob/1.0.0/plugins/comments/controllers/actions/EditAction.php
https://github.com/Cotonti/Cotonti/blob/1.0.0/system/cache.php
https://github.com/Cotonti/Cotonti/issues/1894
https://github.com/Cotonti/Cotonti/pull/1897
https://www.vulncheck.com/advisories/cotonti-1.0.0-php-object-injection-via-comments-plugin-edit-action-cb-parameter

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