CVE-2023-6937

NameCVE-2023-6937
DescriptionwolfSSL 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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs1059357

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
wolfssl (PTS)bullseye4.6.0+p1-0+deb11u2vulnerable
bookworm5.5.4-2+deb12u1vulnerable
trixie5.6.6-1.2fixed
sid5.6.6-1.3fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
wolfsslsourceexperimental5.6.6-1
wolfsslsource(unstable)5.6.6-1.21059357

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

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