Medium (5.9). EPSS 3.1% chance of exploitation in the next 30 days.
PuTTY 0.68 through 0.73 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).
Severity
CVSS 3.1
5.9 medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS
3.1% chance of exploitation in the next 30 days; higher than 87% of CVEs (scores of 2026-10-31)