# openSUSE-SU-2021:0160-1: Security update for stunnel

> An attacker can bypass certificate chain verification in stunnel when the redirect option is used with verifyChain enabled, potentially allowing man-in-the-middle attacks.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Jan 2021

## What is openSUSE-SU-2021:0160-1?

openSUSE-SU-2021:0160-1 is a vulnerability in stunnel, published on 25 Jan 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

This update for stunnel fixes the following issues:

Security issue fixed:

- The 'redirect' option was fixed to properly handle 'verifyChain = yes' (bsc#1177580).

Non-security issues fixed:

- Fix startup problem of the stunnel daemon (bsc#1178533)

- update to 5.57:
  * Security bugfixes
  * New features
    - New securityLevel configuration file option.
    - Support for modern PostgreSQL clients
    - TLS 1.3 configuration updated for better compatibility.
  * Bugfixes
    - Fixed a transfer() loop bug.
    - Fixed memory leaks on configuration reloading errors.
    - DH/ECDH initialization restored for client sections.
    - Delay startup with systemd until network is online.
    - A number of testing framework fixes and improvements.

- update to 5.56:
  - Various text files converted to Markdown format.
  - Support for realpath(3) implementations incompatible
    with POSIX.1-2008, such as 4.4BSD or Solaris.
  - Support for engines without PRNG seeding methods (thx to
    Petr Mikhalitsyn).
  - Retry unsuccessful port binding on configuration
    file reload.
  - Thread safety fixes in SSL_SESSION object handling.
  - Terminate clients on exit in the FORK threading model.

- Fixup stunnel.conf handling:
  * Remove old static openSUSE provided stunnel.conf.
  * Use upstream stunnel.conf and tailor it for openSUSE using sed.
  * Don't show README.openSUSE when installing.

- enable /etc/stunnel/conf.d
- re-enable openssl.cnf

This update was imported from the SUSE:SLE-15-SP2:Update update project.

## Which versions are affected by openSUSE-SU-2021:0160-1?


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `stunnel` | openSUSE:Leap 15.2 | All versions | 5.57-lp152.2.3.1 |

## How do I fix openSUSE-SU-2021:0160-1?

Upgrade to a fixed version.

## Is openSUSE-SU-2021:0160-1 being exploited?

There is no known exploitation of openSUSE-SU-2021:0160-1 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for openSUSE-SU-2021:0160-1 and fix it if it is affected.

What it is: openSUSE-SU-2021:0160-1 is a vulnerability in stunnel, published on 25 Jan 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of openSUSE-SU-2021:0160-1 in the wild and no public exploit code.

Affected product: stunnel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/openSUSE-SU-2021-0160-1/ (Markdown: https://insights.sbomify.com/openSUSE-SU-2021-0160-1/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/openSUSE-SU-2021:0160-1

---
From sbomify Insights: https://insights.sbomify.com/openSUSE-SU-2021-0160-1/
Summaries are generated and may contain mistakes; the official description above is the record.