docs: add SECURITY.md

Document security vulnerability reporting process.

Minor fixes in other docs, and add OpenSSF badge.

Signed-off-by: Andrey Smirnov <andrey.smirnov@siderolabs.com>

CONTRIBUTING.md

@@ -1,5 +1,7 @@
 # Contributing
 
+More information about contributing to Talos can be found in the [Documentation](https://www.talos.dev/latest/learn-more/developing-talos/).
+
 ## Developer Certificate of Origin
 
 All commits require a [DCO](https://developercertificate.org/) sign-off.

README.md

@@ -10,6 +10,9 @@
     <a href="https://github.com/talos-systems/talos/releases/latest">
       <img alt="Pre-release" src="https://img.shields.io/github/release-pre/talos-systems/talos.svg?label=pre-release&logo=GitHub&logoColor=white&style=flat-square">
     </a>
+    <a href="https://www.bestpractices.dev/projects/7340">
+      <img src="https://www.bestpractices.dev/projects/7340/badge" alt="OpenSSF badge">
+    </a>
   </p>
 </p>
 
@@ -31,14 +34,14 @@ For instructions on deploying and managing Talos, see the [Documentation](https:
 
 ## Community
 
+- Support: Questions, bugs, feature requests [GitHub Discussions](https://github.com/siderolabs/talos/discussions)
 - Slack: Join our [slack channel](https://slack.dev.talos-systems.io)
-- Support: Questions, bugs, feature requests [GitHub Discussions](https://github.com/talos-systems/talos/discussions)
 - Forum: [community](https://groups.google.com/a/SideroLabs.com/forum/#!forum/community)
 - Twitter: [@SideroLabs](https://twitter.com/SideroLabs)
 - Email: [info@SideroLabs.com](mailto:info@SideroLabs.com)
 
 If you're interested in this project and would like to help in engineering efforts or have general usage questions, we are happy to have you!
-We hold a weekly meeting that all audiences are welcome to attend.
+We hold a monthly meeting that all audiences are welcome to attend.
 
 We would appreciate your feedback so that we can make Talos even better!
 To do so, you can take our [survey](https://docs.google.com/forms/d/1TUna5YTYGCKot68Y9YN_CLobY6z9JzLVCq1G7DoyNjA/edit).
@@ -59,8 +62,8 @@ See [Contributing](CONTRIBUTING.md) for our guidelines.
 
 ## License
 
-<a href="https://github.com/talos-systems/talos/blob/master/LICENSE">
-  <img alt="GitHub" src="https://img.shields.io/github/license/talos-systems/talos?style=flat-square">
+<a href="https://github.com/siderolabs/talos/blob/master/LICENSE">
+  <img alt="GitHub" src="https://img.shields.io/github/license/siderolabs/talos?style=flat-square">
 </a>
 
 Some software we distribute is under the General Public License family

SECURITY.md

@@ -0,0 +1,13 @@
+# Reporting Security Issues
+
+The Sidero Labs team and community take security bugs in Talos Linux seriously. We appreciate your efforts to responsibly disclose your findings, and will make every effort to acknowledge your contributions.
+
+To report a security issue, please use the GitHub Security Advisory ["Report a Vulnerability"](https://github.com/siderolabs/talos/security/advisories/new) tab.
+
+The Sidero Labs team will send a response indicating the next steps in handling your report. After the initial reply to your report, the security team will keep you informed of the progress towards a fix and full announcement, and may ask for additional information or guidance. The expected response time is within 3 business days, and the fix is expected to be delivered within 30 days.
+
+## Supported Releases
+
+The Sidero Labs team will only provide security updates for the two latest minor releases of Talos Linux. If you are using an older version of Talos Linux, we recommend upgrading to the latest release.
+
+For example, if the latest release is `v1.8.3`, the supported releases are `v1.7.x` and `v1.8.x`.