--- title: "CVE-2026-70367\n | Ubuntu" description: Ubuntu is an open source software operating system that runs from the desktop, to the cloud, to all your internet connected things. url: https://ubuntu.com/security/CVE-2026-70367?format=md keywords: index, follow --- # CVE-2026-70367 Publication date 4 August 2026 Last updated 7 August 2026 --- Ubuntu priority **Medium** [Why this priority?](https://ubuntu.com/security/cves/about#priority ) Toggle side navigation ## 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. ## Status Show unmaintained releases | Package | Ubuntu Release | Status | | --- | --- | --- | --- * [How can I get the fixes?](https://ubuntu.com/security/cves/about#security) * [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses) ## References * [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-70367) * [NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-70367) * [Launchpad](https://launchpad.net/bugs/cve/CVE-2026-70367) * [Debian](https://security-tracker.debian.org/tracker/CVE-2026-70367) ### Other references * * *