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CRITICAL

CVE-2026-91939

CVSS v3

9.8

CRITICAL

EPSS Score

1.0 %

exploit probability, as of 2026-09-28

CISA KEV

No

known exploited

Exploitation

—

SSVC status

Description

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.

Technical details

Published
2026-09-15
Last Modified
2026-09-16

Frequently asked questions

What is CVE-2026-91939?

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.

Is CVE-2026-91939 actively exploited?

Active exploitation of CVE-2026-91939 has not been confirmed. Its EPSS score was 1.0% on 2026-09-28, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-91939?

CVE-2026-91939 has a CVSS v3 base score of 9.8 (CRITICAL severity).

Is CVE-2026-91939 affecting your environment?

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