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Improper Input ValidationWeakness · CWE-20

CVE-2026-48107

MEDIUM · 6.5 CVSS v3.1 Published 2026-06-10
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
72/100
Remediation priority · Elevated
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Russh is a Rust SSH client & server library. From version 0.37.0 to before version 0.61.0, in the russh client keyboard-interactive authentication path, a malicious SSH server could send a USERAUTH_INFO_REQUEST with an attacker-controlled prompt count, and the client would use that raw count directly in Vec::with_capacity(...) before validating that enough prompt data was actually present in the packet. This issue has been patched in version 0.61.0.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

In russh versions 0.37.0 through before 0.61.0, the SSH client keyboard-interactive authentication handler processes USERAUTH_INFO_REQUEST packets by using an attacker-supplied prompt count value directly in Vec::with_capacity() allocation without first validating that sufficient prompt data follows in the packet. This allows a malicious server to trigger excessive memory allocation, potentially causing denial of service through memory exhaustion.

MitigationUpgrade russh to version 0.61.0 or later. If upgrade is not immediately feasible, consider restricting keyboard-interactive authentication or implementing connection timeout limits to mitigate potential memory exhaustion attacks.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify russh library version
    Run 'cargo tree -p russh' or inspect your Cargo.lock file to find the installed russh version. If using a binary, check its dependency list or vendor documentation.
    Affected if The installed version is 0.37.0 through 0.60.x inclusive.
  2. Confirm keyboard-interactive authentication is in use
    Review application logs, SSH configuration, or connection settings to determine whether the SSH client authenticates using keyboard-interactive (interactive) method rather than password-only or public-key.
    Affected if The application uses keyboard-interactive authentication with russh.
  3. Verify russh handles server auth challenges
    Check if the SSH client code processes USERAUTH_INFO_REQUEST packets from the server, which is part of keyboard-interactive authentication flow.
    Affected if The code path processes server-sent authentication info requests.

You are affected if your application uses russh version 0.37.0 through 0.60.x and performs keyboard-interactive authentication, allowing a malicious server to send oversized prompt counts to trigger excessive memory allocation.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade russh to version 0.61.0 or later. If upgrade is not immediately feasible, consider restricting keyboard-interactive authentication or implementing connection timeout limits to mitigate potential memory exhaustion attacks.

Recommended fix High confidence

0.61.0

  1. Check the current russh version in your project by running `cargo tree | grep russh` or examining your Cargo.lock file
  2. Update your Cargo.toml dependency to specify russh version 0.61.0 or later: change `russh = "..."` to `russh = ">=0.61.0"`
  3. Run `cargo update russh` to update the dependency to the fixed version
  4. Rebuild your project with `cargo build` to verify the upgrade compiles successfully
  5. Test that SSH keyboard-interactive authentication still functions correctly with your server

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,040
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-48107 in production — separate from our analysis above.

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What this is

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