CVE-2026-58317 Integer overflow in TTSSH2
An attacker can trigger an integer conversion error in TTSSH2 to read adjacent memory or crash the Tera Term SSH client.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-58317?
CVE-2026-58317 is a medium-severity vulnerability in TeraTerm Project TTSSH2, published on 17 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
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.
Weakness: CWE-196
Which versions are affected by CVE-2026-58317?
How do I fix CVE-2026-58317?
No fix has been published for CVE-2026-58317 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-58317 being exploited?
There is no known exploitation of CVE-2026-58317 in the wild and no public exploit code.
Sources
Also known as GHSA-mmcg-pw3p-cwjh.