CVE-2023-1667 Null dereference in libssh

What is CVE-2023-1667?

CVE-2023-1667 is a medium-severity vulnerability in Debian Debian Linux, published on 26 May 2023. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

A NULL pointer dereference was found In libssh during re-keying with algorithm guessing. This issue may allow an authenticated client to cause a denial of service.

Weakness: CWE-476

Which versions are affected by CVE-2023-1667?

It affects 4 products.

Products include Debian Debian Linux, Fedoraproject Fedora, Libssh Libssh, Redhat Enterprise Linux.

How do I fix CVE-2023-1667?

Apply the vendor's patch.

Is CVE-2023-1667 being exploited?

There is no known exploitation of CVE-2023-1667 in the wild and no public exploit code.

Other vulnerabilities in Debian Debian Linux

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• CVE-2025-49113 RoundCube Webmail Deserialization of Untrusted Data Exploited Critical 9.9
• CVE-2026-24061 GNU InetUtils Argument Injection Exploited Critical 9.8
• CVE-2025-39682 Linux Kernel Improper Check for Unusual or Exceptional Conditions Exploited Critical 9.8
• CVE-2024-9680 Mozilla Firefox Use-After-Free Exploited Critical 9.8

All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2023-1667, GHSA-fx73-x3p9-h2wf, UBUNTU-CVE-2023-1667.