dbcve.org
Ios XrOperating system · Cisco

CVE-2021-34722

MEDIUM · 6.7 CVSS v3.1 Published 2021-09-09
Fix available
A fix is available. Upgrade to 7.3.2 / 7.4.1 or later.
See remediation →
69/100
Remediation priority · Elevated
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
Multiple vulnerabilities in the CLI of Cisco IOS XR Software could allow an authenticated, local attacker to gain access to the underlying root shell of an affected device and execute arbitrary commands with root privileges. For more information about these vulnerabilities, see the Details section of this advisory.

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 · moderate confidence

Multiple CLI vulnerabilities in Cisco IOS XR Software allow an authenticated local attacker to bypass restrictions and gain access to the underlying root shell, enabling execution of arbitrary commands with root privileges.

MitigationApply Cisco's IOS XR software patches; limit CLI access to trusted administrators and implement monitoring for unauthorized root shell access.

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
Ios XrOperating system
Affected:>= 7.1.1, < 7.3.2>= 7.4.0, < 7.4.1

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
Local
Complexity
Low
Privileges
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:H/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. Determine IOS XR software version
    Log into the device CLI and run the command 'show version' to display the installed Cisco IOS XR software version. Look for the version number in the output.
    Affected if The displayed version falls within 7.1.1 to 7.3.1, or is exactly 7.4.0.
  2. Check for root shell access availability
    From an authenticated CLI session with standard user privileges, attempt to access the root shell by running commands like 'run bash' or 'admin' followed by 'root' to see if restrictions can be bypassed.
    Affected if A non-privileged authenticated user can obtain root shell access without proper authorization.
  3. Review current user privilege levels
    Execute 'show privilege' and 'show users' commands to list all active user sessions and their current privilege levels.
    Affected if Unexpected users or sessions are present at root or admin privilege level.
  4. Inspect CLI access control configuration
    Run 'show running-config | include user' or 'show running-config | include privilege' to review how CLI users and privileges are configured.
    Affected if Configuration shows weak or missing privilege restrictions on CLI commands.

You are affected if your Cisco IOS XR version is 7.1.1 through 7.3.1 or 7.4.0, and authenticated local users can bypass CLI restrictions to access the root shell.

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 7.3.2 / 7.4.1 or later
Fixed in 7.3.27.4.1
Interim mitigation

Apply Cisco's IOS XR software patches; limit CLI access to trusted administrators and implement monitoring for unauthorized root shell access.

Recommended fix High confidence

7.3.2 or 7.4.1 (or any version >= 7.4.1, or >= 7.3.2 but < 7.4.0)

  1. 1. Identify the current IOS XR version by running 'show version' on the device
  2. 2. Based on your current version, determine the appropriate upgrade path: if running 7.1.1 to 7.3.x, upgrade to 7.3.2 or later; if running 7.4.0, upgrade to 7.4.1 or later
  3. 3. Review Cisco IOS XR release notes for version 7.3.2 and 7.4.1 to check for any compatibility requirements or migration considerations
  4. 4. Download the appropriate fixed IOS XR software image from Cisco (requires valid Cisco service contract)
  5. 5. Follow Cisco's standard IOS XR upgrade procedure: back up current configuration, transfer new image to device, verify image integrity, perform upgrade with 'install add' and 'install activate' commands
  6. 6. After upgrade, verify the device is operational and running the fixed version with 'show version'
  7. 7. Confirm the vulnerability is remediated by attempting to reproduce the command injection (in a test environment only)
Caveat IOS XR major version upgrades may introduce configuration or feature changes; review release notes and test in non-production environment before deploying

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

Fix this in Ios Xr Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing5.0 h
  • Review / QA3.0 h
18.0 hours of engineering $3,170
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,072.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-34722 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2021-34722 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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