Description
PuTTY 0.77 before 0.84 uses a copy of the PuTTY icon as a trust indication for TELNET data but the trust status is not cleared between proxy authentication and the main session.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| PuTTY | PuTTY | 0.77 – < 0.84 | 0.84 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | putty | 0.84-1 | — |
| Debian 13 | putty | No fix yet | — |
| Debian 12 | putty | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | putty | No fix yet | — |
| Ubuntu 26.04 LTS | putty | No fix yet | — |
| Ubuntu 25.10 | putty | No fix yet | — |
| Ubuntu 24.04 LTS | putty | No fix yet | — |
| Ubuntu 22.04 LTS | putty | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | putty | No fix yet | — |
| Ubuntu 18.04 LTS | putty | No fix yet | — |
| Ubuntu 16.04 LTS | putty | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | putty | 0.85-2.1 | openSUSE-SU-2026:12168-1 |
| openSUSE Leap 16.0 | putty | 0.85-bp160.1.1 | openSUSE-SU-2026:22127-1 |
Advisories 3
- WID-SEC-2026-1673 PuTTY: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 1, 2026
- openSUSE-SU-2026:22127-1 Security update for putty SUSE / openSUSE Security Updates · Oct 20, 2026
- openSUSE-SU-2026:12168-1 putty-0.85-2.1 on GA media SUSE / openSUSE Security Updates · Oct 18, 2026