dbcve.org
Policy SuiteApplication · Cisco

CVE-2021-40119

CRITICAL · 9.8 CVSS v3.1 Published 2021-11-04
Fix available
A fix is available. Upgrade to 21.1.0 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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
A vulnerability in the key-based SSH authentication mechanism of Cisco Policy Suite could allow an unauthenticated, remote attacker to log in to an affected system as the root user. This vulnerability is due to the re-use of static SSH keys across installations. An attacker could exploit this vulnerability by extracting a key from a system under their control. A successful exploit could allow the attacker to log in to an affected system as the root user.

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

Cisco Policy Suite contains a vulnerability in its SSH key-based authentication where static SSH keys are reused across installations. An attacker can extract SSH keys from one compromised system and use them to authenticate as root to any other affected Cisco Policy Suite installation, gaining full remote access.

MitigationRegenerate all static SSH host keys on affected systems and update authorized_keys. Apply Cisco patches if available. Implement key rotation procedures to prevent reuse in future deployments.

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

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Policy SuiteApplication
Affected:< 21.1.0

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
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 installed Cisco Policy Suite version
    Run 'show version' or check /opt/cps/version file if accessible via administrative console. Compare the version number to the affected range: any version before 21.1.0 is vulnerable.
    Affected if Installed version is below 21.1.0
  2. Confirm SSH service is enabled
    Check if SSH daemon is running on the system. Look for sshd process or check /etc/ssh/sshd_config for configuration. The vulnerability only applies if SSH is active.
    Affected if SSH service is enabled and accepting connections
  3. Locate SSH host keys
    Examine standard SSH host key locations: /etc/ssh/ssh_host_rsa_key, /etc/ssh/ssh_host_ecdsa_key, /etc/ssh/ssh_host_ed25519_key. These keys are used for host authentication.
    Affected if SSH host keys exist on the system
  4. Check for static/reused key indicators
    Review SSH host key files. If the same key material is found across multiple CPS installations or matches known default key patterns, the system is using reusable keys.
    Affected if SSH host keys appear to be identical across different installations or are known static keys

System is affected if Cisco Policy Suite version is below 21.1.0 and SSH with key-based authentication is enabled, allowing potential authentication using keys extracted from other compromised installations.

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
Upgrade available Upgrade to 21.1.0 or later
Fixed in 21.1.0
Interim mitigation

Regenerate all static SSH host keys on affected systems and update authorized_keys. Apply Cisco patches if available. Implement key rotation procedures to prevent reuse in future deployments.

Recommended fix High confidence

21.1.0 or later

  1. Plan a maintenance window for the Cisco Policy Suite upgrade
  2. Back up current system configuration and data
  3. Download Cisco Policy Suite version 21.1.0 or later from Cisco
  4. Follow Cisco's official upgrade documentation for Policy Suite
  5. After upgrade, regenerate SSH host keys on the affected system using standard SSH key generation procedures
  6. Verify SSH access works with the new keys
  7. Confirm root access is secured and only authorized keys are present in /root/.ssh/authorized_keys

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

Fix this in Policy Suite Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,980
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,968.

Scan for this in your stack

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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-2021-40119 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data