Go to homepageCyberStrike

Menu

Star on GitHub · 3.2k
Sign inDownload

CVE-2011-0539

7.5 · HIGH

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…

Published Feb 10, 2011openbsdCWE-264EPSS 1.81%

Overview

CVE-2011-0539 is a high-severity vulnerability affecting openbsd openssh. It was published on February 10, 2011 and has a CVSS 3.1 base score of 7.5 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical 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.

Remediation

Check the references section for vendor advisories and patches from openbsd. Update openssh to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected products

VendorProductVersionsStatus

References

Refh20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=c02794777Refkb.juniper.net/InfoCenter/index?page=content&id=JSA10673Refsecunia.com/advisories/43181Refsecunia.com/advisories/44269Refwww.openssh.com/txt/legacy-cert.advRefwww.openwall.com/lists/oss-security/2011/02/04/2Refwww.securityfocus.com/bid/46155Refwww.securitytracker.com/id?1025028Refwww.vupen.com/english/advisories/2011/0284Refexchange.xforce.ibmcloud.com/vulnerabilities/65163

How CyberStrike helps

Frequently asked questions

What is CVE-2011-0539?

CVE-2011-0539 is a high-severity vulnerability affecting openbsd openssh. It was published on February 10, 2011 and has a CVSS 3.1 base score of 7.5 (HIGH).

How severe is CVE-2011-0539?

This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2011-0539?

Check the references section for vendor advisories and patches from openbsd. Update openssh to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2011-0539?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2011-0539 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

Related HIGH CVEs from 2011

View all
Browse by year2026202520242023202220212020201920182017201620152014201320122011201020092008200720062005200420032002200120001999