CVE-2026-70367
Stunnel: ssrf bypass in stunnel socks proxy via ipv4-mapped ipv6 loopback and unspecified addresses allows access to loopback-only services
- State
- Published
- Severity
- 5.4 Medium
- Published
- Aug 4, 2026
- Updated
- Aug 6, 2026
- Reserved
- Aug 4, 2026
Description
A Server-Side Request Forgery (SSRF) bypass vulnerability exists in “stunnel” 5.79 and lower when configured in SOCKS proxy mode. This flaw allows a client to bypass intended localhost restrictions by using IPv4-mapped IPv6 addresses (e.g., “::ffff:127.0.0.1”) or unspecified addresses ("0.0.0.0", "::"), enabling access to loopback-only services on the "stunnel" host that should not be network-reachable.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 5.4 Medium | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N | redhat |
Weaknesses
- CWE-918 Server-Side Request Forgery (SSRF)
Affected Products
| Product | Versions |
|---|---|
stunnelMobi-Com Polska Sp. z o.o. |
|
Red Hat Enterprise Linux 10Red Hat | |
Red Hat Enterprise Linux 6Red Hat | |
Red Hat Enterprise Linux 7Red Hat | |
Red Hat Enterprise Linux 8Red Hat | |
Red Hat Enterprise Linux 9Red Hat |
References
- https://access.redhat.com/security/cve/CVE-2026-70367vdb-entry
- RHBZ#2462083issue-tracking
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