CVE-2026-128087
russh kex_done: shared-secret callback runs before server host-key verification
Description
russh is a Rust SSH client and server library that includes an SSH agent protocol implementation. From version 0.55.0 until version 0.65.1, the initial key exchange invokes client::Handler::kex_done() with the raw shared secret before check_server_key() accepts the server host key or certificate. A malicious SSH server can therefore trigger application-defined secondary-channel initialization or early data handling even when the server identity is subsequently rejected. Ordinary clients that keep the callback's no-op default or independently defer callback-derived actions until trust is confirmed are not affected. This issue is fixed in version 0.65.1.
INFO
Published Date :
Nov. 13, 2026, 7:19 p.m.
Last Modified :
Nov. 13, 2026, 7:19 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-128087
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | LOW | [email protected] | ||||
| CVSS 3.1 | LOW | MITRE-CVE |
Solution
- Update russh to version 0.65.1 or later.
- Ensure server identity is verified before using shared secret.
- Review and update key exchange handling logic.
- Test updated implementation thoroughly.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-128087.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-128087 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-128087
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-128087 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-128087 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Nov. 13, 2026
Action Type Old Value New Value Added Description russh is a Rust SSH client and server library that includes an SSH agent protocol implementation. From version 0.55.0 until version 0.65.1, the initial key exchange invokes client::Handler::kex_done() with the raw shared secret before check_server_key() accepts the server host key or certificate. A malicious SSH server can therefore trigger application-defined secondary-channel initialization or early data handling even when the server identity is subsequently rejected. Ordinary clients that keep the callback's no-op default or independently defer callback-derived actions until trust is confirmed are not affected. This issue is fixed in version 0.65.1. Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N Added CWE CWE-696 Added CWE CWE-863 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/128xxx/CVE-2026-128087.json">CVE-2026-128087</a> Added Reference https://github.com/Eugeny/russh/commit/43a46d67a80a7355fcd2fb25e7e00d79aec8184c Added Reference https://github.com/Eugeny/russh/pull/808 Added Reference https://github.com/Eugeny/russh/releases/tag/v0.65.1 Added Reference https://github.com/Eugeny/russh/security/advisories/GHSA-9264-jvgf-6w2f