CVE-2026-91143
goproxy through 15.3 Authentication Bypass via CONNECT
- State
- Published
- Severity
- 6.9 Medium
- Published
- Sep 14, 2026
- Updated
- Sep 24, 2026
- Reserved
- Sep 14, 2026
Description
goproxy through 15.3 fails to apply HTTP proxy basic authentication to CONNECT tunnel requests, allowing unauthenticated clients to bypass credential requirements. Attackers can issue CONNECT requests to establish tunnels through the authenticated proxy without providing credentials, enabling arbitrary TCP traffic relay and access to restricted destinations.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.9 Medium | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N | VulnCheck |
| 3.1 | 7.2 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N | VulnCheck |
Weaknesses
- CWE-288 Authentication Bypass Using an Alternate Path or Channel
Affected Products
| Product | Versions |
|---|---|
goproxysnail007 |
|
References
- Researcher write-upthird-party-advisoryexploit
- utils/structs.go at v15.3technical-description
- services/http.go at v15.3technical-description
- https://github.com/snail007/goproxyproduct
- VulnCheck Advisory: goproxy through 15.3 Authentication Bypass via CONNECTthird-party-advisory
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