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iOSOperating system · Cisco

CVE-2025-20172

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, Cisco IOS XE Software, and Cisco IOS XR 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. For Cisco IOS and IOS XE Software, a successful exploit could allow the attacker to cause the device to reload unexpectedly, resulting in a DoS condition. For Cisco IOS XR Software, a successful exploit could allow the attacker to cause the SNMP process to restart, resulting in an interrupted SNMP response from an affected device. Devices that are running Cisco IOS XR Software will not reload.  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 denial of service vulnerability exists in the SNMP subsystem of Cisco IOS, IOS XE, and IOS XR software due to improper error handling when parsing crafted SNMP requests. An authenticated attacker with valid SNMP credentials (community string for v1/v2c or user credentials for v3) can send a specially crafted SNMP request that causes affected devices to either reload unexpectedly (IOS/IOS XE) or restart the SNMP process (IOS XR), resulting in service disruption.

MitigationRestrict SNMP access via ACLs to trusted management networks, migrate to SNMPv3 with authentication and encryption, change any exposed community strings, and apply Cisco software updates when available.

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\(33\)sre= 12.2\(33\)sre0a= 12.2\(33\)sre1= 12.2\(33\)sre2= 12.2\(33\)sre3= 12.2\(33\)sre4= 12.2\(33\)sre5= 12.2\(33\)sre6= 12.2\(33\)sre7= 12.2\(33\)sre7a= 12.2\(33\)sre8= 12.2\(33\)sre9
Ios XeOperating system
Affected:= 3.2.0se= 3.2.1se= 3.2.2se= 3.2.3se= 3.3.0se= 3.3.0sg= 3.3.1se= 3.3.1sg= 3.3.2se= 3.3.2sg= 3.3.3se= 3.3.4se
Ios XrOperating system
Affected:= 7.0.1= 7.0.2= 7.0.12= 7.0.14= 7.1.1= 7.1.2= 7.1.3= 7.1.15= 7.2.0= 7.2.1= 7.2.2= 7.3.1

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
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 the device OS and version
    Run 'show version' on the device CLI to obtain the exact software version
    Affected if The version matches any of the listed affected versions for IOS, IOS XE, or IOS XR
  2. Check if SNMP is enabled
    Run 'show snmp' or 'show snmp community' to see if SNMP is active and which versions are configured
    Affected if SNMP is enabled (any version) on an affected version device
  3. Determine SNMP configuration type
    Run 'show running-config | include snmp' to see SNMP configuration lines, look for 'snmp-server community' (v1/v2c) or 'snmp-server user' (v3)
    Affected if SNMP v1 or v2c is configured (uses community strings without authentication)
  4. Verify SNMP access control
    Run 'show snmp group' or check ACLs applied to SNMP with 'show ip access-lists' and correlate with SNMP configuration
    Affected if SNMP is accessible from untrusted networks (no ACL restricting SNMP to management IPs)

A device is affected if it runs an affected IOS/IOS XE/IOS XR version AND has SNMP enabled, regardless of whether the attacker has valid credentials.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Restrict SNMP access via ACLs to trusted management networks, migrate to SNMPv3 with authentication and encryption, change any exposed community strings, and apply Cisco software updates when available.

Fix this in iOS Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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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-2025-20172 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