Vulnerability · Published Jul 17, 2026 · Assigned by jpcert
CVE-2026-58317
Medium 6.3
In plain English
A medium-severity security flaw in TTSSH2 from TeraTerm Project. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 25% of all known vulnerabilities).
Official description
Unsigned to Signed Conversion Error (CWE-196) vulnerability exists in TTSSH2 plugin of Tera Term provided by TeraTerm Project. When Tera Term attempts to establish an SSH connection to a server set up by an attacker, out-of-bounds read/write may occur. As a result, the contents of adjacent memory regions may be transmitted to the server, and Tera Term may behave unexpected or terminate abnormally.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| TeraTerm Project | TTSSH2 | 1.00 alpha1 – through 3.6.1 |
Weakness: CWE-196 · Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L