s2n-tls could negotiate signature algorithms not allowed by policy

LowPublished Oct 5, 2023

### Impact s2n-tls clients and servers negotiating TLS1.2 could choose a SHA-1 hash in TLS connection signatures despite their s2n-tls security policy not supporting SHA-1. Customers of AWS services do not need to take action. Applications using s2n-tls should upgrade to the most recent release of s2n-tls. ### Patches The patch is included in s2n-tls v1.3.54 ### Workarounds There is no workaround. Applications using s2n-tls should upgrade to the most recent release of s2n-tls. If you have any questions or comments about this advisory we ask that you contact AWS/Amazon Security via our [vulnerability reporting page](https://aws.amazon.com/security/vulnerability-reporting) or directly via email to [aws-security@amazon.com](mailto:aws-security@amazon.com). Please do not create a public GitHub issue.