putty vulnerabilities and fixes

Recent CVEs affecting putty, with upgrade or downgrade steps. 3 tracked.

putty has 3 tracked vulnerabilities, 0 critical. A fixed release or vendor patch exists for 3. Most recent: 2026-05-25. Highest priority: CVE-2026-48850 (score 24/100).

• CVE-2026-48850 LOW 3.7 UPGRADE PuTTY 0.72 before 0.84 has a double free in RSA KEX.
• CVE-2026-48852 LOW 3.7 UPGRADE PuTTY 0.71 before 0.84 has an assertion failure in ECDSA signature verification.
• CVE-2026-48851 LOW 3.1 UPGRADE PuTTY 0.77 before 0.84 uses a copy of the PuTTY icon as a trust indication for TELNET data but the trust statu

FAQ

How do I fix putty vulnerabilities?

Open the CVE for your version, check the affected range, then follow the listed action: upgrade to the fixed release, or downgrade or mitigate if no fix exists yet. Commands for each OS are shown on every CVE page.

Is putty being exploited right now?

None of the tracked putty CVEs are on the CISA Known Exploited Vulnerabilities list at the moment. This is checked every 20 minutes.

Which putty CVE should I patch first?

CVE-2026-48850 currently ranks highest (24/100): PuTTY 0.72 before 0.84 has a double free in RSA KEX..

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