Description
A remotely triggerable memory overwrite in RSA key exchange in PuTTY before 0.71 can occur before host key verification.
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 | 0.70-6 | — |
| Debian 13 | putty | 0.70-6 | — |
| Debian 12 | putty | 0.70-6 | — |
| Debian 9 | putty | 0.67-3+deb9u1 | DSA-4423-1 |
| Debian 8 | putty | 0.63-10+deb8u2 | DLA-1763-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | putty | No fix yet | — |
| Ubuntu 16.04 LTS | putty | 0.67-3+deb9u1build0.16.04.1 | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SUSE Package Hub 15 | putty | 0.71-bp150.4.3.1 | openSUSE-SU-2019:1123-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.0 | putty | 0.71-lp150.9.1 | openSUSE-SU-2019:1113-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | putty | 0.71-r0 | — |
| Alpine v3.23 | putty | 0.71-r0 | — |
| Alpine v3.22 | putty | 0.71-r0 | — |
| Alpine v3.21 | putty | 0.71-r0 | — |
| Alpine v3.20 | putty | 0.71-r0 | — |
Show 14 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | putty | 0.71-r0 | — |
| Alpine v3.18 | putty | 0.71-r0 | — |
| Alpine v3.17 | putty | 0.71-r0 | — |
| Alpine v3.16 | putty | 0.71-r0 | — |
| Alpine v3.15 | putty | 0.71-r0 | — |
| Alpine v3.14 | putty | 0.71-r0 | — |
| Alpine v3.13 | putty | 0.71-r0 | — |
| Alpine v3.12 | putty | 0.71-r0 | — |
| Alpine v3.11 | putty | 0.71-r0 | — |
| Alpine v3.10 | putty | 0.71-r0 | — |
| Alpine v3.9 | putty | 0.71-r0 | — |
| Alpine v3.8 | putty | 0.71-r0 | — |
| Alpine v3.7 | putty | 0.71-r0 | — |
| Alpine v3.6 | putty | 0.71-r0 | — |
Advisories 4
- DSA-4423-1 putty - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-1763-1 putty - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2019:1113-1 Security update for putty SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2019:1123-1 Security update for putty SUSE / openSUSE Security Updates · Feb 4, 2026
References
- https://www.chiark.greenend.org.uk/~sgtatham/putty/changes.html
- FEDORA-2019-5776dfe300 vendor-advisory
- FEDORA-2019-9e1a1cd634 vendor-advisory
- openSUSE-SU-2019:1113 vendor-advisory
- openSUSE-SU-2019:1123 vendor-advisory
- 20190403 [SECURITY] [DSA 4423-1] putty security update mailing-list
- https://security.netapp.com/advisory/ntap-20190404-0001/
- DSA-4423 vendor-advisory
- [debian-lts-announce] 20190424 [SECURITY] [DLA 1763-1] putty security update mailing-list