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iOSOperating system · Cisco

CVE-2009-0626

HIGH · 7.8 CVSS v2.0 Published 2009-03-27
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
The SSLVPN feature in Cisco IOS 12.3 through 12.4 allows remote attackers to cause a denial of service (device reload or hang) via a crafted HTTPS packet.

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

Denial of service vulnerability in Cisco IOS SSLVPN feature affecting versions 12.3 through 12.4. Remote unauthenticated attackers can cause affected devices to reload or hang by sending specially crafted HTTPS packets to the SSLVPN service.

MitigationApply Cisco IOS patches or upgrade to a fixed version beyond 12.4 that addresses this vulnerability. Plan maintenance window and ensure backup configurations before upgrade.

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:= 12.3= 12.3b= 12.3bc= 12.3bw= 12.3ja= 12.3jea= 12.3jeb= 12.3jec= 12.3jk= 12.3jl= 12.3jx= 12.3t

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' or 'show ios version' on the device CLI to retrieve the installed IOS version string (for example, 12.3(11)T or 12.4(15)T)
    Affected if The version matches 12.3.x, 12.3, or 12.4.x variants listed in the affected versions (12.3, 12.3b, 12.3bc, 12.3bw, 12.3ja, 12.3jea, 12.3jeb, 12.3jec, 12.3jk, 12.3jl, 12.3jx, 12.3t, or 12.4 versions)
  2. Determine if SSLVPN (WebVPN) is configured
    Run 'show webvpn' or 'show sslvpn' to check if SSLVPN/WebVPN is enabled on the device
    Affected if SSLVPN or WebVPN is actively configured and running on the device
  3. Verify HTTPS service is listening for SSLVPN
    Run 'show ip http server status' or 'show running-config | include webvpn' to confirm the HTTPS service is bound to SSLVPN functionality
    Affected if HTTPS service is enabled and serving SSLVPN/WebVPN connections (typically port 443)
  4. Check for active SSLVPN sessions
    Run 'show webvpn session' or 'show sslvpn session' to see if any SSLVPN sessions are active
    Affected if Any SSLVPN sessions are active, indicating the vulnerable service is reachable

You are affected if the device runs a Cisco IOS version between 12.3 and 12.4 and has SSLVPN/WebVPN enabled with HTTPS access exposed.

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

Apply Cisco IOS patches or upgrade to a fixed version beyond 12.4 that addresses this vulnerability. Plan maintenance window and ensure backup configurations before upgrade.

Fix this in iOS Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2009-0626 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