Server-Side Request Forgery (SSRF) Affecting stunnel4 package, versions *


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
0.26% (16th percentile)

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  • Snyk IDSNYK-DEBIAN13-STUNNEL4-20507560
  • published5 Oct 2026
  • disclosed4 Aug 2026

Introduced: 4 Aug 2026

CVE-2026-70367  (opens in a new tab)
CWE-918  (opens in a new tab)

How to fix?

There is no fixed version for Debian:13 stunnel4.

NVD Description

Note: Versions mentioned in the description apply only to the upstream stunnel4 package and not the stunnel4 package as distributed by Debian. See How to fix? for Debian:13 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1