How severe is CVE-2020-3552?

CVE-2020-3552 has a CVSS 3.x base score of 7.4, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2020-3552 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-3552?

CVE-2020-3552 primarily affects Cisco Wireless Lan Controller. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-3552?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2020-3552 published?

CVE-2020-3552 was published on 2020-09-24 and last updated on 2026-06-17.

CVE-2020-3552

CVE-2020-3552 is a high-severity vulnerability in Cisco Wireless Lan Controller with a CVSS 3.x base score of 7.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.

Key facts

Severity: High (CVSS 3.x base score 7.4)
CVSS v2: 6.1
EPSS exploit prediction: 0% (38th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-476
Affected product: Cisco Wireless Lan Controller
Published: 2020-09-24
Last modified: 2026-06-17

Description

A vulnerability in the Ethernet packet handling of Cisco Aironet Access Points (APs) Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by connecting as a wired client to the Ethernet interface of an affected device and sending a series of specific packets within a short time frame. A successful exploit could allow the attacker to cause a NULL pointer access that results in a reload of the affected device.

Frequently asked questions

What is CVE-2020-3552?: A vulnerability in the Ethernet packet handling of Cisco Aironet Access Points (APs) Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by connecting as a wired client to the Ethernet interface of an affected device and sending a series of specific packets within a short time frame. A successful exploit could allow the attacker to cause a NULL pointer access that results in a reload of the affected device.
How severe is CVE-2020-3552?: CVE-2020-3552 has a CVSS 3.x base score of 7.4, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2020-3552 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-3552?: CVE-2020-3552 primarily affects Cisco Wireless Lan Controller. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-3552?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2020-3552 published?: CVE-2020-3552 was published on 2020-09-24 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ap-ethport-dos-xtjTt8pY

Affected products (4)

cpe:2.3:o:cisco:wireless_lan_controller:*:*:*:*:*:*:*:*
cpe:2.3:a:cisco:business_access_points:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:access_points:*:*:*:*:*:*:*:*
cpe:2.3:a:cisco:aironet_access_point_software:8.10\(1.255\):*:*:*:*:*:*:*

More vulnerabilities in Cisco Wireless Lan Controller

CVE-2014-0703 — Critical (CVSS 10.0): Cisco Wireless LAN Controller (WLC) devices 7.4 before 7.4.110.0 distribute Aironet IOS software with a race condition…
CVE-2020-3560 — High (CVSS 8.6): A vulnerability in Cisco Aironet Access Points (APs) could allow an unauthenticated, remote attacker to cause a denial…
CVE-2020-3559 — High (CVSS 8.6): A vulnerability in Cisco Aironet Access Point (AP) Software could allow an unauthenticated, remote attacker to cause an…
CVE-2018-0417 — High (CVSS 7.8): A vulnerability in TACACS authentication with Cisco Wireless LAN Controller (WLC) Software could allow an…
CVE-2014-0707 — High (CVSS 7.8): Cisco Wireless LAN Controller (WLC) devices 7.2, 7.3, and 7.4 before 7.4.110.0 allow remote attackers to cause a denial…
CVE-2014-0706 — High (CVSS 7.8): Cisco Wireless LAN Controller (WLC) devices 7.2 before 7.2.115.2, 7.3, and 7.4 before 7.4.110.0 allow remote attackers…

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Other CWE-476 (NULL Pointer Dereference) vulnerabilities

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CVE-2020-14500 — Critical (CVSS 10.0): Secomea GateManager all versions prior to 9.2c, An attacker can send a negative value and overwrite arbitrary data.
CVE-2010-2495 — Critical (CVSS 10.0): The pppol2tp_xmit function in drivers/net/pppol2tp.c in the L2TP implementation in the Linux kernel before 2.6.34 does…
CVE-2026-46195 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: smb: client: validate dacloffset before building…
CVE-2026-31657 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: batman-adv: hold claim backbone gateways by…
CVE-2026-31436 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: dmaengine: idxd: fix possible wrong descriptor…

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