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CVE-2026-46705— russh server userauth state is not reset when authentication principal changes

Quick assessment

Affected
Eugeny russh
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Russh是Eugene个人开发者的一个 Rust SSH 客户端和服务器端库。 Russh 0.34.0-beta.1版本至0.61.0之前版本存在授权问题漏洞，该漏洞源于服务器认证路径在请求主体变化时未分离内部认证状态，可能导致状态不匹配。

CVSS 5.3 · Medium EPSS 0.36% · P28

Affected Version Matrix 1

VendorProduct Version RangeStatus
Eugeny russh >= 0.34.0-beta.1, < 0.61.0 affected
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I. Basic Information for CVE-2026-46705

Vulnerability Information
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Vulnerability Title
russh server userauth state is not reset when authentication principal changes
Source: CVE Program / CVE List V5
Vulnerability Description
Russh is a Rust SSH client & server library. From version 0.34.0-beta.1 to before version 0.61.0, the russh server authentication path keeps internal userauth state across SSH_MSG_USERAUTH_REQUEST messages without separating that state when the request principal changes. RFC 4252 allows the user name and service name fields to change between authentication requests. The issue is not that such changes are invalid. The issue is that russh-owned authentication state, such as remaining methods, partial-success state, and in-progress method state, can remain associated with the connection and then influence a later request for a different (user, service). This is an internal library state mismatch. This issue has been patched in version 0.61.0.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
认证机制不恰当
Source: CVE Program / CVE List V5
Vulnerability Title
Russh 授权问题漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Russh是Eugene个人开发者的一个 Rust SSH 客户端和服务器端库。 Russh 0.34.0-beta.1版本至0.61.0之前版本存在授权问题漏洞，该漏洞源于服务器认证路径在请求主体变化时未分离内部认证状态，可能导致状态不匹配。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Eugeny russh >= 0.34.0-beta.1, < 0.61.0 -

II. Public POCs for CVE-2026-46705

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III. Intelligence Information for CVE-2026-46705

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Vendor Advisories for CVE-2026-46705 (1)

Same Patch Batch · Eugeny · 2026-06-10 · 6 CVEs total

CVE-2026-48110 7.5 HIGH Russh: SSH message fields were decoded through allocation-first parsers before field-speci
CVE-2026-46702 7.5 HIGH Russh: Post-decompression SSH packet size was not bounded, allowing remote oversized compr
CVE-2026-46673 7.5 HIGH Russh: Unchecked CryptoVec allocation and growth handling is reachable from local agent in
CVE-2026-48107 6.5 MEDIUM Russh: Unchecked keyboard-interactive prompt count in client auth path
CVE-2026-48108 5.3 MEDIUM Russh: SSH identification parsing accepted non-canonical client banners and did not bound

IV. Related Vulnerabilities

Same product: russh
Same vendor: Eugeny
Same weakness: CWE-287

V. Comments for CVE-2026-46705

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