DescriptionA timing side-channel in the handling of RSA ClientKeyExchange messages was discovered in GnuTLS. This side-channel can be sufficient to recover the key encrypted in the RSA ciphertext across a network in a Bleichenbacher style attack. To achieve a successful decryption the attacker would need to send a large amount of specially crafted messages to the vulnerable server. By recovering the secret from the ClientKeyExchange message, the attacker would be able to decrypt the application data exchanged over that connection.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub advisories/code/issues, web search, more)
ReferencesDLA-3321-1, DSA-5349-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
gnutls28 (PTS)buster3.6.7-4+deb10u8vulnerable
buster (security)3.6.7-4+deb10u10fixed
bullseye (security), bullseye3.7.1-5+deb11u3fixed
bookworm, sid3.7.9-2fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs

Fixed by: (3.8.0)
Code cleanup: (3.8.0)

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