# CVE-2026-79786

## Summary

- **CVE ID:** CVE-2026-79786
- **Severity:** HIGH
- **CVSS Score:** 7.1 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N)
- **CWE:** CWE-601
- **Published:** Aug 25, 2026
- **Last Modified:** Aug 28, 2026

## Description

Coroot's unauthenticated MCP OAuth dynamic client registration endpoint accepts any syntactically valid redirect URI without validation, allowing attackers to register clients pointing to attacker-controlled hosts. Attackers can send authorization URLs to signed-in users, capture their authorization codes upon consent approval, and exchange them for access tokens to hijack MCP sessions.

## Affected Products

- coroot — coroot (1.20.2)

## References

- [CNA](https://github.com/coroot/coroot)
- [CNA](https://github.com/coroot/coroot/issues/929)
- [CNA](https://github.com/coroot/coroot/blob/v1.24.5/api/mcp_oauth.go)
- [CNA](https://www.vulncheck.com/advisories/coroot-1.20.2-through-1.24.5-unvalidated-redirect-uri-in-mcp-oauth-client-registration)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.22%
- **EPSS Percentile:** 12.4

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._