Server-Side Request Forgery (SSRF) Affecting stunnel package, versions <5.82-r0


Severity

Recommended
0.0
medium
0
10

Snyk's Security Team recommends NVD's CVSS assessment. Learn more

Threat Intelligence

EPSS
0.26% (16th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-ALPINE324-STUNNEL-20260482
  • published29 Sept 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?

Upgrade Alpine:3.24 stunnel to version 5.82-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream stunnel package and not the stunnel package as distributed by Alpine. See How to fix? for Alpine:3.24 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