iOSOperating system · Cisco
CVE-2024-20276
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 · uneditedA vulnerability in Cisco IOS Software for Cisco Catalyst 6000 Series Switches could allow an unauthenticated, adjacent attacker to cause an affected device to reload unexpectedly. This vulnerability is due to improper handling of process-switched traffic. An attacker could exploit this vulnerability by sending crafted traffic to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition.
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 confidenceA denial of service vulnerability in Cisco IOS Software for Catalyst 6000 Series switches exists due to improper handling of process-switched traffic. An unauthenticated adjacent attacker can send crafted traffic to cause the affected device to reload unexpectedly, resulting in DoS.
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
= 15.5\(1\)sy5= 15.5\(1\)sy6= 15.5\(1\)sy7= 15.5\(1\)sy8= 15.5\(1\)sy9= 15.5\(1\)sy10= 15.5\(1\)sy11CVSS 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
- Adjacent
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:A/AC:L/PR:N/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 checksWork through these to decide whether this CVE applies to you.
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Confirm device is a Catalyst 6000 Series switchRun 'show version' or 'show inventory' and identify the model number in the outputAffected if The device model is not a Cisco Catalyst 6000 Series switch (the vulnerability only affects this product line)
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Identify the IOS versionRun 'show version' and locate the 'IOS (tm)' or 'Version' line in the outputAffected if The device is running Cisco IOS but the version cannot be determined from the output
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Compare installed version to affected releasesLook for version strings matching 15.5(1)SY5, 15.5(1)SY6, 15.5(1)SY7, 15.5(1)SY8, 15.5(1)SY9, 15.5(1)SY10, or 15.5(1)SY11 in the 'show version' outputAffected if The installed version is exactly 15.5(1)SY5, 15.5(1)SY6, 15.5(1)SY7, 15.5(1)SY8, 15.5(1)SY9, 15.5(1)SY10, or 15.5(1)SY11
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Assess network exposure to adjacent attackersReview the network topology and access control lists to determine if unauthenticated adjacent attackers can send traffic to the deviceAffected if The device is directly accessible to unauthenticated adjacent attackers on the same network segment
A user is affected if they are running a Catalyst 6000 Series switch with IOS version 15.5(1)SY5, SY6, SY7, SY8, SY9, SY10, or SY11, and the device is reachable by adjacent attackers on the same network segment.
Generated from the published advisory. Verify against your own configuration.
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 dataApply the Cisco IOS software update for Catalyst 6000 Series switches that addresses this vulnerability; until patched, limit adjacent network access to reduce exposure.
Fix this in iOS
Scoped from the published advisory
- Consultation6.0 h
- Implementation4.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,608.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2024-20276 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2024-20276 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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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.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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