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iOSOperating system · Cisco

CVE-2025-20171

HIGH · 7.7 CVSS v3.1 Published 2025-02-05
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
83/100
Remediation priority · High
Remotely reachable 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 SNMP subsystem of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated, remote attacker to cause a DoS condition on an affected device. This vulnerability is due to improper error handling when parsing SNMP requests. An attacker could exploit this vulnerability by sending a crafted SNMP request to an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly, resulting in a DoS condition.  This vulnerability affects SNMP versions 1, 2c, and 3. To exploit this vulnerability through SNMP v2c or earlier, the attacker must know a valid read-write or read-only SNMP community string for the affected system. To exploit this vulnerability through SNMP v3, the attacker must have valid SNMP user credentials for the affected system.

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

A vulnerability in the SNMP subsystem of Cisco IOS and IOS XE Software allows an authenticated, remote attacker to cause device reload via crafted SNMP requests. The root cause is improper error handling during SNMP request parsing, affecting SNMP versions 1, 2c, and 3.

MitigationRestrict SNMP access to trusted management networks, use SNMPv3 with strong authentication/encryption, apply Cisco-provided patches when available, and disable SNMP if not required.

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
iOSOperating system
Affected:= 12.2\(33\)cx= 12.2\(33\)cy= 12.2\(33\)cy1= 12.2\(33\)cy2= 12.2\(33\)ira= 12.2\(33\)irb= 12.2\(33\)irc= 12.2\(33\)ird= 12.2\(33\)ire= 12.2\(33\)ire1= 12.2\(33\)ire2= 12.2\(33\)irf
Ios XeOperating system
Affected:= 3.2.0se= 3.2.0sg= 3.2.1se= 3.2.1sg= 3.2.2se= 3.2.2sg= 3.2.3se= 3.2.3sg= 3.2.4sg= 3.2.5sg= 3.2.6sg= 3.2.7sg

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
Low
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/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 device OS and version
    Execute 'show version' on the device CLI to display the running Cisco IOS or IOS XE version
    Affected if The displayed version matches any of the affected Cisco iOS 12.2(33) variants (cx, cy, cy1, cy2, ira, irb, irc, ird, ire, ire1, ire2, irf) or Cisco IOS XE 3.2.x versions (0se through 7sg)
  2. Verify SNMP is enabled
    Execute 'show snmp' or 'show snmp group' to check if the SNMP subsystem is actively running
    Affected if SNMP is enabled and the device shows as listening on SNMP ports or has SNMP groups configured
  3. Confirm SNMP version configuration
    Execute 'show snmp view' or 'show snmp community' to see which SNMP versions (v1, v2c, v3) are configured
    Affected if SNMP versions 1, 2c, or 3 are enabled on the device, as all three are affected by this vulnerability
  4. Check SNMP community strings
    Execute 'show snmp community' to list configured SNMP community strings
    Affected if Any SNMP community strings exist (v1/v2c) or SNMPv3 users are configured, indicating SNMP access is active

The device is affected if it runs Cisco IOS 12.2(33) with any of the listed suffixes or Cisco IOS XE 3.2.0-3.2.7, and has SNMP enabled with any of versions 1, 2c, or 3 configured.

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

Restrict SNMP access to trusted management networks, use SNMPv3 with strong authentication/encryption, apply Cisco-provided patches when available, and disable SNMP if not required.

Recommended fix Moderate confidence

Obtain fixed release version from Cisco Security Advisory at sec.cloudapps.cisco.com - fixed versions are not specified in available CVE documentation

  1. 1. Identify the specific Cisco IOS or IOS XE software version currently running on the device using 'show version'
  2. 2. Access the Cisco Security Advisory at sec.cloudapps.cisco.com for CVE-2025-20171 to obtain the specific fixed software releases
  3. 3. Plan an upgrade to a fixed release of Cisco IOS or IOS XE software that addresses this vulnerability
  4. 4. Before upgrading, back up the current device configuration
  5. 5. During maintenance window, upgrade the device to the fixed software release
  6. 6. Verify the device reloads successfully and SNMP functionality operates normally
  7. 7. As a temporary mitigation, restrict SNMP access to only trusted management networks using ACLs on the SNMP interface configuration
  8. 8. For SNMPv2c, ensure SNMP community strings are strong and changed from defaults; for SNMPv3, ensure only valid users exist with proper authentication
Caveat Review Cisco IOS upgrade documentation for potential compatibility issues with existing configurations and ensure the target fixed release supports all required features

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

Fix this in iOS Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,970
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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-2025-20171 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