| Package | openssh |
|---|---|
| Version | 1:7.4p1-10+deb9u10 (stretch), 1:7.9p1-10+deb10u5 (buster) |
| Related CVEs | CVE-2025-26465 |
The Qualys Threat Research Unit (TRU) discovered that the OpenSSH client is vulnerable to a machine-in-the-middle attack if the VerifyHostKeyDNS option is enabled (disabled by default).
The client side in OpenSSH 5.7 through 8.4 has an Observable Discrepancy leading to an information leak in the algorithm negotiation. This allows man-in-the-middle attackers to target initial connection attempts (where no host key for the server has been cached by the client). This issue was assigned CVE-2020-14145. Completely removing this information leak would cause other problems, but this update includes a partial mitigation by preferring the default ordering if the user has a key that matches the best-preference default algorithm.
In addition, the stretch update contains a regression introduced with the fix for CVE-2023-48795, which could cause segmentation faults under some circumstances.
For Debian 10 buster, these problems have been fixed in version 1:7.9p1-10+deb10u5.
For Debian 9 stretch, these problems have been fixed in version 1:7.4p1-10+deb9u10.
We recommend that you upgrade your openssh packages.
Further information about Extended LTS security advisories can be found in the dedicated section of our website.