CVE-2011-0539

Publication date 10 February 2011

Last updated 6 June 2026

Ubuntu priority

Cvss 3 Severity Score

Description

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.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
openssh	10.10 maverick	Not affected
	10.04 LTS lucid	Not affected
	9.10 karmic	Not affected
	8.04 LTS hardy	Not affected
	6.06 LTS dapper	Not affected

Notes

jdstrand

only version 5.6 and 5.7

Severity score breakdown

CVSS version: CVSS v3.0

Base score 7.5 · High

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality impact	High
Integrity impact	None
Availability impact	None

Scores

Parameter	Value
Base score	7.5 · High
Exploitability score	-
Impact score	-

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N