Description
The ssh_agent_channel_data function in PuTTY before 0.68 allows remote attackers to have unspecified impact via a large length value in an agent protocol message and leveraging the ability to connect to the Unix-domain socket representing the forwarded agent connection, which trigger a buffer overflow.
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 | 0.67-3 | — |
| Debian 13 | putty | 0.67-3 | — |
| Debian 12 | putty | 0.67-3 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | putty | 0.67-3build0.16.04.1 | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | putty | 0.76-1.2 | openSUSE-SU-2024:11201-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.5 | putty | 0.68-r0 | — |
| Alpine v3.4 | putty | 0.68-r0 | — |
| Alpine v3.3 | putty | 0.68-r0 | — |
| Alpine v3.2 | putty | 0.68-r0 | — |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Exploit-DB 1
- PuTTY < 0.68 - 'ssh_agent_channel_data' Integer Overflow Heap Corruption EDB-42137 · dos · Jun 7, 2017 · verified
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 1
- openSUSE-SU-2024:11201-1 putty-0.76-1.2 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
References
- 97156 vdb-entry
- 42137 exploit
- GLSA-201703-03 vendor-advisory
- https://git.tartarus.org/?p=simon/putty.git%3Ba=commitdiff%3Bh=4ff22863d895cb7ebfced4cf923a012a614adaa8
- 1038067 vdb-entry
- http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/vuln-agent-fwd-overflow.html
- openSUSE-SU-2017:0741 vendor-advisory
- GLSA-201706-09 vendor-advisory