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iOSOperating system · Cisco

CVE-2009-2867

HIGH · 7.8 CVSS v2.0 Published 2009-09-28
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
87/100
Remediation priority · High
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
Unspecified vulnerability in Cisco IOS 12.2XNA, 12.2XNB, 12.2XNC, 12.2XND, 12.4T, 12.4XZ, and 12.4YA, when Zone-Based Policy Firewall SIP Inspection is enabled, allows remote attackers to cause a denial of service (device reload) via a crafted SIP transit packet, aka Bug ID CSCsr18691.

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

This is an unspecified vulnerability in Cisco IOS versions 12.2XNA through 12.2XND, 12.4T, 12.4XZ, and 12.4YA. When Zone-Based Policy Firewall with SIP Inspection is enabled, a remote attacker can send a specially crafted SIP (Session Initiation Protocol) transit packet to cause the device to reload, resulting in a denial of service.

MitigationUpgrade to a patched Cisco IOS version or apply the relevant security update. If immediate patching is not possible, consider disabling SIP inspection if not required, or implement ACLs to filter suspicious SIP traffic at network boundaries.

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:= 12.2xna= 12.2xnb= 12.2xnc= 12.2xnd= 12.4t= 12.4xz= 12.4ya= 12.4yb

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
Authentication
None
Confidentiality
None
Integrity
None
Availability
Complete

AV:N/AC:L/Au:N/C:N/I:N/A:C

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 Cisco IOS version
    Run 'show version' on the device CLI and locate the software version string (e.g., 12.4(15)T1)
    Affected if The version matches or falls within 12.2xna through 12.2xnd, 12.4t, 12.4xz, or 12.4ya train
  2. Verify Zone-Based Policy Firewall is configured
    Run 'show zone-pair security' to list configured zone-pairs and their policy configurations
    Affected if Any zone-pair shows a policy-map configured (indicating ZBFW is active)
  3. Confirm SIP inspection is enabled
    Run 'show policy-map type inspect zone-pair' and look for the 'sip' protocol in the inspect configuration, or run 'show class-map type inspect' to list inspected protocols
    Affected if SIP protocol inspection is explicitly configured in the policy-map for an active zone-pair

The device is affected if it runs a vulnerable IOS version within the 12.2XNA through 12.2XND, 12.4T, 12.4XZ, or 12.4YA trains AND has Zone-Based Policy Firewall with SIP inspection actively enabled on a zone-pair.

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

Upgrade to a patched Cisco IOS version or apply the relevant security update. If immediate patching is not possible, consider disabling SIP inspection if not required, or implement ACLs to filter suspicious SIP traffic at network boundaries.

Fix this in iOS Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,480
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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-2009-2867 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