Public Date:
1614973: CVE-2018-10933 libssh: Authentication Bypass due to improper message callbacks implementation
A vulnerability was found in libssh's server-side state machine. A malicious client could create channels without first performing authentication, resulting in unauthorized access.

Find out more about CVE-2018-10933 from the MITRE CVE dictionary dictionary and NIST NVD.


This vulnerability affects libssh shipped in Red Hat Enterprise Linux 7 Extras. No libssh packages are included in Red Hat Enterprise Linux 6 and earlier. This issue does not affect libssh2 or openssh.

This issue can only be affect applications that use libssh to implement an SSH server; SSH client functionality is not affected. No packages in Red Hat products use libssh to implement an SSH server. Therefore, no package from Red Hat that uses the libssh library is affected by this flaw.

The libssh library is available for customer or third party code to use. Such code that is linked against libssh and uses the ssh_bind* functions may be affected by this flaw.

CVSS v3 metrics

NOTE: The following CVSS v3 metrics and score provided are preliminary and subject to review.

CVSS3 Base Score 9.1
CVSS3 Base Metrics CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality High
Integrity Impact High
Availability Impact None

Affected Packages State

Platform Package State
Red Hat Enterprise Linux 8 libssh Not affected
Red Hat Enterprise Linux 8 libssh2 Not affected
Red Hat Enterprise Linux 7 libssh2 Not affected
Red Hat Enterprise Linux 7 libssh Affected
Red Hat Enterprise Linux 6 libssh2 Not affected
Unless explicitly stated as not affected, all previous versions of packages in any minor update stream of a product listed here should be assumed vulnerable, although may not have been subject to full analysis.


Red Hat would like to thank the libssh team for reporting this issue. Upstream acknowledges Peter Winter-Smith (NCC Group) as the original reporter.

External References

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