CVE-2026-91939 Cotonti Comments - Insecure Deserialization

Cotonti 1.0.0 Comments plugin contains a PHP object injection caused by passing the ci GET parameter to unserialize() without allowed_classes restriction, letting unauthenticated attackers instantiate arbitrary PHP objects to manipulate database or execute code, exploit requires crafted serialized payload.

CVSS base score 9.8 /10
Critical
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.98% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Insecure Deserialization
Impact
Remote Code Execution, Data Tampering
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
15 September 2026
Updated
15 October 2026
Weakness
CWE-502

Vendor fix

Update to the latest version with allowed_classes restriction in unserialize() or apply patches to restrict unserialize usage.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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