DescriptionAn issue was discovered in Mbed TLS 3.5.x before 3.6.0. When negotiating the TLS version on the server side, it can fall back to the TLS 1.2 implementation of the protocol if it is disabled. If the TLS 1.2 implementation was disabled at build time, a TLS 1.2 client could put a TLS 1.3-only server into an infinite loop processing a TLS 1.2 ClientHello, resulting in a denial of service. If the TLS 1.2 implementation was disabled at runtime, a TLS 1.2 client can successfully establish a TLS 1.2 connection with the server.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
mbedtls (PTS)buster2.16.0-1undetermined
buster (security)2.16.9-0~deb10u1undetermined
sid, trixie2.28.8-1undetermined

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs


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