Russh: Pre-auth DoS via unbounded allocation in keyboard-interactive auth
Priority HIGH 72CWE-770Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-770.
Summary
Russh is a Rust SSH client & server library. Prior to version 0.60.1, a pre-authentication denial-of-service vulnerability exists in the server's keyboard-interactive authentication handler. A malicious client can crash any russh-based server that implements keyboard-interactive auth (e.g., for 2FA/TOTP) with a single malformed packet, requiring no credentials. This issue has been patched in version 0.60.1.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00481 41st percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed russh (Eugeny): 0.60.1russh (crates.io): 0.60.1
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Eugeny | russh | before 0.60.1 | 0.60.1 | Patch available | CNA |
| — | russh (crates.io) | before 0.60.1 | 0.60.1 | Patch available | GHSA-f5v4-2wr6-hqmg |
- russh VendorEugeny Affected before 0.60.1 Fixed in 0.60.1 Patch available CNA
- russh (crates.io) Vendor— Affected before 0.60.1 Fixed in 0.60.1 Patch available GHSA-f5v4-2wr6-hqmg
CPE configurations NVD · 2
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:russh_project:russh:*:*:*:*:*:rust:*:* | before 0.60.1 | Vulnerable | Russh Project |
| cpe:2.3:a:warpgate_project:warpgate:*:*:*:*:*:*:*:* | before 0.23.1 | Vulnerable | warp-tech |
- cpe:2.3:a:russh_project:russh:*:*:*:*:*:rust:*:* Versions before 0.60.1 Vulnerable ·Russh Project
- cpe:2.3:a:warpgate_project:warpgate:*:*:*:*:*:*:*:* Versions before 0.23.1 Vulnerable ·warp-tech
Remediation
- Fix · CNA russh (Eugeny) Fixed in 0.60.1
- Fix · GHSA-f5v4-2wr6-hqmg russh (crates.io) Fixed in 0.60.1 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-42189
- 2026-10-03 Alias added: GHSA-f5v4-2wr6-hqmg
- 2026-10-25 EPSS moved to the below the 50th percentile
References
More Eugeny vulnerabilities
- TI-2026-65512 russh: Client-side channel-scoped Handler callbacks fire for channel IDs the client never opened CVSS 3.1HIGH 7.5
- TI-2026-35550 Russh: SSH message fields were decoded through allocation-first parsers before field-specific bounds CVSS 3.1HIGH 7.5
- TI-2026-34331 Russh: Post-decompression SSH packet size was not bounded, allowing remote oversized compressed packets CVSS 3.1HIGH 7.5
- TI-2026-34308 Resource allocation without limits in Eugeny russh CVSS 3.1HIGH 7.5
- TI-2025-16084 Tabby has a TCC Bypass via Misconfigured Node Fuses CVSS 4.0HIGH 8.6
- TI-2024-36991 Tabby has a TCC Bypass via Unnecessary Permissive Entitlements in Tabby CVSS 4.0HIGH 8.6
Sources
- CVE-2026-42189 · CVE Program
- CVE-2026-42189 · NVD
- FIRST EPSS
- GHSA-f5v4-2wr6-hqmg · GitHub Advisory Database · CC BY 4.0
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