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Fencer Intel
medium 5.9

CVE-2016-0739 json

libssh before 0.7.3 improperly truncates ephemeral secrets generated for the (1) diffie-hellman-group1 and (2) diffie-hellman-group14 key e…

published 2016-04-13 10 y ago modified 2026-06-17 4 mo ago also EUVD-2016-0763

cvss
5.9
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.4%
EPSS 2.4% chance of exploitation in 30 days, percentile 84%
public exploits
0
none known

Summary

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."

Patch / fix

  • libssh Debian 14, Debian 13, Debian 12 0.6.3-4.3

debian advisories DEBIAN-CVE-2016-0739

  • libssh Ubuntu 14.04 LTS 0.6.1-0ubuntu3.3
  • libssh Ubuntu 16.04 LTS 0.6.3-4.2ubuntu1

ubuntu advisories UBUNTU-CVE-2016-0739

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libssh RHEL 7 EXTRAS_OTHER 0.7.1-2.el7

red hat advisories RHSA-2016:0566

  • libssh SLED 12 SP1, SLED 12, SLE Workstation Extension 12 SP1 +3 more 0.6.3-11.1
  • libssh SLED 11 SP4, SLE Software Development Kit 11 SP4 0.2-5.22.1

suse advisories SUSE-SU-2016:0625-1SUSE-SU-2016:0622-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2016-0739 updated cvss 5.8

libssh: bits/bytes confusion resulting in truncated Difffie-Hellman secret length

  • Red Hat Enterprise Linux 7 Extras libssh 0.7.1-2.el7
    fixed: vendor fix RHSA-2016:0566

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.43% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.0 5.9 CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:P/I:N/A:N

Classification

Weakness
  • CWE-200 Exposure of Sensitive Information to an Unauthorized Actor

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.