CVE-2023-6937 Improper (D)TLS key boundary enforcement

What is CVE-2023-6937?

CVE-2023-6937 is a medium-severity vulnerability in Wolfssl Wolfssl, published on 15 Feb 2024.

Official description

wolfSSL prior to 5.6.6 did not check that messages in one (D)TLS record do not span key boundaries. As a result, it was possible to combine (D)TLS messages using different keys into one (D)TLS record. The most extreme edge case is that, in (D)TLS 1.3, it was possible that an unencrypted (D)TLS 1.3 record from the server containing first a ServerHello message and then the rest of the first server flight would be accepted by a wolfSSL client. In (D)TLS 1.3 the handshake is encrypted after the ServerHello but a wolfSSL client would accept an unencrypted flight from the server. This does not compromise key negotiation and authentication so it is assigned a low severity rating.

Weakness: CWE-20

Which versions are affected by CVE-2023-6937?

It affects 1 product.

Products include Wolfssl Wolfssl.

How do I fix CVE-2023-6937?

Upgrade to a fixed version.

Is CVE-2023-6937 being exploited?

There is no known exploitation of CVE-2023-6937 in the wild and no public exploit code.

Other vulnerabilities in Wolfssl Wolfssl

• CVE-2024-5991 Buffer overread in domain name matching Critical 10.0
• CVE-2021-37155 Security feature bypass in n/a Critical 9.8
• CVE-2020-36177 Memory corruption in n/a Critical 9.8
• CVE-2014-2896 Memory corruption in n/a Critical 9.8
• CVE-2014-2897 Memory corruption in n/a Critical 9.8

All Wolfssl Wolfssl vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2023-6937, GHSA-ff3x-q8pg-rh37, JLSEC-2026-679, UBUNTU-CVE-2023-6937.