CVE-2016-0739

Severity: medium (CVSS 5.9 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2016-04-13 · updated 2026-06-17
Weakness: CWE-200

Description

libssh before 0.7.3 improperly truncates ephemeral secrets generated for the (1) diffie-hellman-group1 and (2) diffie-hellman-group14 key exchange methods to 128 bits, which makes it easier for man-in-the-middle attackers to decrypt or intercept SSH sessions via unspecified vectors, aka a "bits/bytes confusion bug."

Affected products

Canonical Ubuntu Linux: 12.04, 14.04, 15.10
Debian Linux: 7.0, 8.0
Fedoraproject Fedora: 22, 23
libssh: through 0.7.2
Red Hat Enterprise Linux: 7.0

References

http://lists.fedoraproject.org/pipermail/package-announce/2016-February/178058.html
http://lists.fedoraproject.org/pipermail/package-announce/2016-March/178822.html
http://lists.opensuse.org/opensuse-updates/2016-03/msg00111.html
http://rhn.redhat.com/errata/RHSA-2016-0566.html
http://www.debian.org/security/2016/dsa-3488
http://www.ubuntu.com/usn/USN-2912-1
https://puppet.com/security/cve/CVE-2016-0739
https://security.gentoo.org/glsa/201606-12
https://www.libssh.org/2016/02/23/libssh-0-7-3-security-and-bugfix-release/
https://www.libssh.org/security/advisories/CVE-2016-0739.txt
http://lists.fedoraproject.org/pipermail/package-announce/2016-February/178058.html
http://lists.fedoraproject.org/pipermail/package-announce/2016-March/178822.html

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