CVE-2023-6937

Name	CVE-2023-6937
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.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs	1059357

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
wolfssl (PTS)	bullseye	4.6.0+p1-0+deb11u2	vulnerable
	bookworm	5.5.4-2+deb12u1	vulnerable
	sid, trixie	5.6.6-1.3	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
wolfssl	source	experimental	5.6.6-1
wolfssl	source	(unstable)	5.6.6-1.2			1059357

Notes

[bookworm] - wolfssl <no-dsa> (Minor issue)
[bullseye] - wolfssl <no-dsa> (Minor issue)
https://github.com/wolfSSL/wolfssl/blob/v5.6.6-stable/ChangeLog.md#vulnerabilities