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Servers and applications

CVE-2011-0539

The key_certify function in usr.bin/ssh/key.c in OpenSSH 5.6 and 5.7, when generating legacy certificates using the -t command-line option in ssh-keygen, does not initialize the nonce field, which might allow remote attackers to obtain sensitive stack memory contents or make it easier to conduct hash collision attacks.

Severity
High 7.5
Published
10 Feb 2011
Last changed
16 Jun 2026
Added to UpHeron
21 Oct 2026
Exploit chance
1.8% in the next 30 daysHigher than 79% of CVEs. EPSS by FIRST, 12 Nov 2026
Weakness
CWE-264CWE-457
Attack
Over the network · No login needed · No user action needed
Attacker can
Read data
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Sources
NVD

Affected software

SoftwareAffected versions
OpenSSHServers and applications · cpe:a:openbsd:openssh
  • Version 5.6
  • Version 5.7

References

  • NVD https://nvd.nist.gov/vuln/detail/CVE-2011-0539
  • CVE.org https://www.cve.org/CVERecord?id=CVE-2011-0539