---
id: CVE-2026-93869
title: >-
  Cotonti through 1.0.0 contains an open redirect vulnerability in the
  cot_url_check() function that validates redirect destinations using a regular
  expression lacking an end-of-string anchor
summary: >-
  Cotonti through 1.0.0 contains an open redirect vulnerability in the
  cot_url_check() function that validates redirect destinations using a regular
  expression lacking an end-of-string anchor. Attackers can bypass the redirect
  guard by sup…
severity: medium
cvss: 6.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'
cwe:
  - CWE-601
vendor: Cotonti
product: Cotonti
affected:
  - Cotonti <= 1.0.0
published: '2026-09-18'
updated: '2026-09-22'
sourceUpdated: '2026-09-22T20:53:07.383'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93869'
references:
  - url: 'https://github.com/Cotonti/Cotonti'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/Cotonti/Cotonti/blob/1.0.0/plugins/ratings/ratings.ajax.php
    label: disclosure@vulncheck.com
  - url: 'https://github.com/Cotonti/Cotonti/blob/1.0.0/system/functions.php'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/Cotonti/Cotonti/issues/1891'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/Cotonti/Cotonti/pull/1899'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/cotonti-through-1.0.0-open-redirect-via-unanchored-cot-url-check-regex
    label: disclosure@vulncheck.com
  - url: 'https://github.com/Cotonti/Cotonti/issues/1891'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
epss: 0.0036
epssPercentile: 0.27165
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-21T15:16:19.097293Z'
ingestedAt: '2026-09-18T20:51:25.688Z'
---

## Overview

Cotonti through 1.0.0 contains an open redirect vulnerability in the cot_url_check() function that validates redirect destinations using a regular expression lacking an end-of-string anchor. Attackers can bypass the redirect guard by supplying hostnames beginning with the site domain to redirect users to attacker-controlled hosts through the ratings plugin or other redirect callers.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.