CVE-2026-91939

Exploitation

Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.

SSVC decision

• ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
• AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
• Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.97% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 62.0% of scored records. A rank, not a probability.

NVD base score

9.3 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

NVD analysis status

Deferred. NVD last modified this record on 2026-09-16.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-09-15 20:56Z1 MO AGO

Last updated

2026-09-24 14:22Z1 MO AGO

Reserved

2026-09-15

Assigning CNA

VulnCheck

Record state

PUBLISHED

Severity

Critical (CVSS 9.3)

CNA CVSS vector

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

Weaknesses

• CWE-502Deserialization of Untrusted DataBase

Data version

5.2

Document digest

1815541c8a1d22432e6b9e6ff48dce17a1a773d041f8c6de832983e03240992f

• github.comGitHub Issue #1888https://github.com/Cotonti/Cotonti/issues/1888issue-tracking
• github.comProposed fix PR #1889 (unmerged)https://github.com/Cotonti/Cotonti/pull/1889patchissue-tracking
• github.comCommentsWidget::run() at 1.0.0https://github.com/Cotonti/Cotonti/blob/1.0.0/plugins/comments/inc/CommentsWidget.phptechnical-description
• github.comAJAX display controller at 1.0.0https://github.com/Cotonti/Cotonti/blob/1.0.0/plugins/comments/controllers/actions/DisplayAction.phptechnical-description
• github.comDefault comments permissions at 1.0.0https://github.com/Cotonti/Cotonti/blob/1.0.0/plugins/comments/comments.setup.phptechnical-description
• github.comhttps://github.com/Cotonti/Cotontiproduct
• www.vulncheck.comVulnCheck Advisory: Cotonti 1.0.0 Comments Plugin PHP Object Injection via ci Parameterhttps://www.vulncheck.com/advisories/cotonti-1.0.0-comments-plugin-php-object-injection-via-ci-parameterthird-party-advisory