CVE-2023-6937

Improper (D)TLS key boundary enforcement

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.

Remediation

Solution:

  • The fix for this issue is located in the following GitHub Pull Request: https://github.com/wolfSSL/wolfssl/pull/7029 https://github.com/wolfSSL/wolfssl/pull/7029 .

Category

5.3
CVSS
Severity: Medium
CVSS 3.1 •
EPSS 0.26%
Vendor Advisory wolfssl.com
Affected: wolfSSL wolfSSL
Published at:
Updated at:

References

Frequently Asked Questions

What is the severity of CVE-2023-6937?
CVE-2023-6937 has been scored as a medium severity vulnerability.
How to fix CVE-2023-6937?
To fix CVE-2023-6937: The fix for this issue is located in the following GitHub Pull Request: https://github.com/wolfSSL/wolfssl/pull/7029 https://github.com/wolfSSL/wolfssl/pull/7029 .
Is CVE-2023-6937 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2023-6937 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2023-6937?
CVE-2023-6937 affects wolfSSL wolfSSL.
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