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Fencer Vulns
high 7.5

CVE-2026-42189 json

Russh: Pre-auth DoS via unbounded allocation in keyboard-interactive auth

published 2026-04-24 6 mo ago modified 2026-10-26 13 d ago also EUVD-2026-28822 , GHSA-f5v4-2wr6-hqmg

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 41%
public exploits
0
none known

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.

Patch / fix

  • crates.io russh 0.60.1
  • russh_project russh 0.60.1
  • warpgate_project warpgate 0.60.1
  • rust-russh Debian 14 0.64.1-1

debian advisories DEBIAN-CVE-2026-42189

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.48% chance of exploitation in the next 30 days, higher than 41% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/Eugeny/russh/security/advisories/GHSA-f5v4-2wr6-hqmg referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
crates.io russh
<0.60.1
0.60.1

Affected products

  • Eugeny russh

Classification

Weakness
  • CWE-770 Allocation of Resources Without Limits or Throttling
  • CWE-789 Memory Allocation with Excessive Size Value

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.