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CVE Record

CVE-2020-3273: Cisco Wireless LAN Controller 802.11 Generic Advertisement Service Denial of Service Vulnerability

A vulnerability in the 802.11 Generic Advertisement Service (GAS) frame processing function of Cisco Wireless LAN Controller (WLC) Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS). The vulnerability is due to incomplete input validation of the 802.11 GAS frames that are processed by an affected device. An attacker could exploit this vulnerability by sending a crafted 802.11 GAS frame over the air to an access point (AP), and that frame would then be relayed to the affected WLC. Also, an attacker with Layer 3 connectivity to the WLC could exploit this vulnerability by sending a malicious 802.11 GAS payload in a Control and Provisioning of Wireless Access Points (CAPWAP) packet to the device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS.

HighCVSS 8.6Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2020-3273 can let an unauthenticated attacker crash a Cisco Wireless LAN Controller, disrupting wireless service. The source describes denial of service only, not data theft or device takeover. Business urgency is high for sites where wireless connectivity supports operations, payments, healthcare, logistics, or guest access.

Executive priority

Treat as high priority where wireless downtime affects revenue, safety, customer access, or operations. Prioritize inventory, vendor guidance review, and remediation scheduling over emergency response unless local evidence shows crashes or exposure from untrusted networks.

Technical view

Cisco WLC Software has incomplete input validation in 802.11 Generic Advertisement Service frame processing. A crafted GAS frame relayed through an AP, or a malicious GAS payload in CAPWAP with Layer 3 connectivity to the WLC, can cause the controller to reload, creating DoS.

Likely exposure

Exposure is likely where Cisco Wireless LAN Controllers process GAS traffic from APs. Attack paths include over-the-air proximity to an AP and Layer 3 connectivity to the WLC. The bundle does not provide exact affected software releases or CPEs.

Exploitation context

The CVE is not listed as KEV in the provided bundle, and no cited source here states active exploitation. Exploitation is unauthenticated and low complexity, but the documented impact is availability loss through device reload.

Researcher notes

The public bundle supports unauthenticated DoS via GAS/CAPWAP handling and CVSS 8.6. It does not include fixed-release details, proof-of-concept status, or confirmed exploitation. Avoid assuming confidentiality or integrity impact beyond the stated availability loss.

Mitigation direction

  • Review Cisco advisory for affected and fixed WLC software guidance.
  • Inventory all Cisco WLC deployments and prioritize business-critical wireless sites.
  • Restrict unnecessary Layer 3 reachability to WLC control interfaces.
  • Validate AP-to-WLC control paths are limited to trusted networks.
  • Plan maintenance for vendor-recommended software updates where applicable.

Validation and detection

  • Identify Cisco WLC models and software versions in use.
  • Compare versions against Cisco advisory and CVE records.
  • Check whether WLCs are reachable from untrusted Layer 3 networks.
  • Review controller logs for unexpected reloads or repeated instability.
  • Confirm wireless service continuity plans cover WLC reload scenarios.
Prepared
Confidence
high
Sources
3

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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cwe · low confidence lookup

CWE-119: Exact CWE lookup

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cve · low confidence lookup

CVE-2020-3273 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
8.6 (3.0)
Known Exploited
No
Published

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
8.6CVSS 3.0HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H3.94Primary CVE score

Vulnerability scoring details

Base CVSS 3.0 score

8.6High
CVSS 3.0 vector shape for CVE-2020-3273Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
CiscoCisco Wireless LAN Controller (WLC)n/aListed
Weakness

CWE details

CWE-119

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.