Description
An issue in AsyncSSH before 2.14.1 allows attackers to control the extension info message (RFC 8308) via a man-in-the-middle attack, aka a "Rogue Extension Negotiation."
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 | python-asyncssh | 2.15.0-1 | — |
| Debian 13 | python-asyncssh | 2.15.0-1 | — |
| Debian 12 | python-asyncssh | 2.10.1-2+deb12u2 | — |
| Debian 11 | python-asyncssh | 2.5.0-0.1+deb11u1 | DLA-3899-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 22.04 LTS | python-asyncssh | 2.5.0-1ubuntu0.1 | USN-7108-1 |
| Ubuntu 20.04 LTS | python-asyncssh | 1.12.2-1ubuntu0.2 | USN-7108-1 |
| Ubuntu 16.04 LTS | python-asyncssh | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 24.04 LTS | python-asyncssh | 2.10.1-2ubuntu0.1+esm1 | USN-7108-1 |
| Ubuntu Pro 18.04 LTS | python-asyncssh | 1.11.1-1ubuntu0.1~esm2 | USN-7108-2 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | python-asyncssh | 2.24.0-1.1 | openSUSE-SU-2026:11851-1 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | asyncssh | < 2.14.1 | 2.14.1 | GHSA-cfc2-wr2v-gxm5 |
Advisories 4
- openSUSE-SU-2026:11851-1 python313-asyncssh-2.24.0-1.1 on GA media SUSE / openSUSE Security Updates · Sep 23, 2026
- USN-7108-2 python-asyncssh vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- USN-7108-1 python-asyncssh vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- DLA-3899-1 python-asyncssh - security update Debian Security (DSA / DLA) · Mar 9, 2026
References
- https://github.com/ronf/asyncssh/security/advisories/GHSA-cfc2-wr2v-gxm5
- FEDORA-2023-d2956318e4 vendor-advisory
- https://www.terrapin-attack.com
- https://github.com/ronf/asyncssh/blob/develop/docs/changes.rst
- https://github.com/advisories/GHSA-cfc2-wr2v-gxm5
- http://packetstormsecurity.com/files/176280/Terrapin-SSH-Connection-Weakening.html
- https://security.netapp.com/advisory/ntap-20231222-0001/