CVE-2026-48850
LowCVSS 3.7Exploitation Probability (EPSS)
Low risk24th percentile - higher than 24% of all known CVEs
Summary
PuTTY versions 0.72 through before 0.84 have a double free vulnerability in RSA KEX handling.
Risk Assessment
The organization may face PuTTY client crashes or potential arbitrary code execution during SSH connections using RSA KEX.
Recommendation
Upgrade PuTTY to version 0.84 or later, which includes a fix for this vulnerability.
Other vulnerabilities in PuTTY
See all- CVE-2017-6542Critical
The ssh_agent_channel_data function in PuTTY before version 0.68 allows remote attackers to have unspecified impact via a large length value in an agent protocol message, leading to a buffer overflow.
- CVE-2026-48852Low
PuTTY versions 0.71 through 0.83 have an assertion failure in ECDSA signature verification. The issue is fixed in version 0.84.
- CVE-2026-48851Low
In PuTTY versions 0.77 through 0.83, the PuTTY icon is used as a trust indicator for TELNET data, but the trust status is not cleared between proxy authentication and the main session.
Original NVD description (English source)
PuTTY 0.72 before 0.84 has a double free in RSA KEX.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS