CVE-2026-91939CWE-502insecure-deserialization

CVE-2026-91939

Critical · published September 16, 2026

CVSS v3.1
9.8
EPSS
1%
Percentile
61.8
In the wild
Unconfirmed
What it is

Cotonti 1.0.0 Comments plugin passes the ci GET parameter to unserialize() without allowed_classes restriction, allowing unauthenticated attackers to instantiate arbitrary PHP classes with attacker-controlled properties. Attackers can exploit PHP object injection through crafted serialized payloads to trigger gadget chains and achieve database manipulation or code execution.

The record
Technical detail
CVSS v3.1
9.8 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
9.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
EPSS
0.00978 · 61.8th percentile
Weakness
CWE-502 · Deserialization of Untrusted Data
Published
2026-09-16T01:16Z
References (8)
https://github.com/Cotonti/Cotonti · [email protected]https://github.com/Cotonti/Cotonti/blob/1.0.0/plugins/comments/comments.setup.php · [email protected]https://github.com/Cotonti/Cotonti/blob/1.0.0/plugins/comments/controllers/actions/DisplayAction.php · [email protected]https://github.com/Cotonti/Cotonti/blob/1.0.0/plugins/comments/inc/CommentsWidget.php · [email protected]https://github.com/Cotonti/Cotonti/issues/1888 · [email protected]https://github.com/Cotonti/Cotonti/pull/1889 · [email protected]https://www.vulncheck.com/advisories/cotonti-1.0.0-comments-plugin-php-object-injection-via-ci-parameter · [email protected]https://github.com/Cotonti/Cotonti/issues/1888 · 134c704f-9b21-4f2e-91b3-4a467353bcc0
EPSS history
Timeline
  • 17 SEP 03:33Z
    EPSS moved — → 1%
    epss
  • 15 SEP 20:56Z
    Cotonti 1.0.0 Comments Plugin PHP Object Injection via ci Parameter
    cvelistv5