CVE-2026-58317 | Unsigned to Signed Conversion Error (CWE-196) vulnerability … | CVSS 5.1 MEDIUM

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.

Metadata

CVE ID: CVE-2026-58317
State: PUBLISHED
Assigner: jpcert
Reserved: 2026-07-10 02:15 UTC
Published: 2026-07-17 04:14 UTC
Last updated: 2026-07-17 04:14 UTC
Primary CWE: CWE-196
Unsigned to signed conversion error
Vendor / Product: TeraTerm Project / TTSSH2
Sources: cve.org · NVD

Severity & Metrics

5.1 MEDIUM CVSS 4.0

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N

Affected products (1)

Vendor	Product	Platform	Versions
TeraTerm Project	TTSSH2	—	1.00 alpha1 ≤ 3.6.1

Weakness (CWE)

CWE	Source	Description
CWE-196	cna	Unsigned to signed conversion error

CVSS scores (2)

Score	Severity	Version	Source	Vector
6.3	MEDIUM	3.0	cna	CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L
5.1	MEDIUM	4.0	cna	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N

References (3)