---
title: "CVE-2026-91939: Cotonti Comments - Insecure Deserialization"
description: "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."
url: https://panop.io/threat-heartbeat/CVE-2026-91939/
---

# 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 ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-91939)

## 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](https://cwe.mitre.org/data/definitions/502.html)

## 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

- [https://nvd.nist.gov/vuln/detail/CVE-2026-91939](https://nvd.nist.gov/vuln/detail/CVE-2026-91939)
- [https://github.com/Cotonti/Cotonti/issues/1888](https://github.com/Cotonti/Cotonti/issues/1888)
- [https://github.com/Cotonti/Cotonti/pull/1889](https://github.com/Cotonti/Cotonti/pull/1889)
- [https://www.vulncheck.com/advisories/cotonti-1.0.0-comments-plugin-php-object-injection-via-ci-parameter](https://www.vulncheck.com/advisories/cotonti-1.0.0-comments-plugin-php-object-injection-via-ci-parameter)
- [https://github.com/Cotonti/Cotonti](https://github.com/Cotonti/Cotonti)
- [https://github.com/Cotonti/Cotonti/blob/1.0.0/plugins/comments/comments.setup.php](https://github.com/Cotonti/Cotonti/blob/1.0.0/plugins/comments/comments.setup.php)
- [https://github.com/Cotonti/Cotonti/blob/1.0.0/plugins/comments/controllers/actions/DisplayAction.php](https://github.com/Cotonti/Cotonti/blob/1.0.0/plugins/comments/controllers/actions/DisplayAction.php)
- [https://github.com/Cotonti/Cotonti/blob/1.0.0/plugins/comments/inc/CommentsWidget.php](https://github.com/Cotonti/Cotonti/blob/1.0.0/plugins/comments/inc/CommentsWidget.php)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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