How severe is CVE-2024-20303?

CVE-2024-20303 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-2024-20303 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2024-20303?

CVE-2024-20303 primarily affects Cisco Ios Xe. In total, 68 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2024-20303?

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.

Does CVE-2024-20303 have an EU (EUVD) identifier?

Yes. CVE-2024-20303 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-18018.

When was CVE-2024-20303 published?

CVE-2024-20303 was published on 2024-03-27 and last updated on 2026-06-17.

CVE-2024-20303

CVE-2024-20303 is a high-severity vulnerability in Cisco Ios Xe 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-459.

Key facts

Severity: High (CVSS 3.x base score 7.4)
EPSS exploit prediction: 0% (24th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2024-18018
Weakness: CWE-459
Affected product: Cisco Ios Xe
Published: 2024-03-27
Last modified: 2026-06-17

Description

A vulnerability in the multicast DNS (mDNS) gateway feature of Cisco IOS XE Software for Wireless LAN Controllers (WLCs) could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition. This vulnerability is due to improper management of mDNS client entries. An attacker could exploit this vulnerability by connecting to the wireless network and sending a continuous stream of specific mDNS packets. A successful exploit could allow the attacker to cause the wireless controller to have high CPU utilization, which could lead to access points (APs) losing their connection to the controller and result in a DoS condition.

Frequently asked questions

What is CVE-2024-20303?: A vulnerability in the multicast DNS (mDNS) gateway feature of Cisco IOS XE Software for Wireless LAN Controllers (WLCs) could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition. This vulnerability is due to improper management of mDNS client entries. An attacker could exploit this vulnerability by connecting to the wireless network and sending a continuous stream of specific mDNS packets. A successful exploit could allow the attacker to cause the wireless controller to have high CPU utilization, which could lead to access points (APs) losing their connection to the controller and result in a DoS condition.
How severe is CVE-2024-20303?: CVE-2024-20303 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-2024-20303 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-20303?: CVE-2024-20303 primarily affects Cisco Ios Xe. In total, 68 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2024-20303?: 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.
Does CVE-2024-20303 have an EU (EUVD) identifier?: Yes. CVE-2024-20303 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-18018.
When was CVE-2024-20303 published?: CVE-2024-20303 was published on 2024-03-27 and last updated on 2026-06-17.

References

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-wlc-mdns-dos-4hv6pBGf

Affected products (68)

cpe:2.3:o:cisco:ios_xe:17.2.1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.2.1a:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.2.1r:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.2.1v:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.2.2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.2.3:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.3.1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.3.1a:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.3.1w:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.3.1x:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.3.1z:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.3.2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.3.2a:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.3.3:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.3.4:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.3.4a:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.3.4b:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.3.4c:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.3.5:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.3.5a:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.3.5b:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.3.6:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.3.7:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.3.8:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.3.8a:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.4.1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.4.1a:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.4.1b:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.4.2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.4.2a:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.5.1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.5.1a:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.6.1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.6.1a:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.6.1w:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.6.1x:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.6.1y:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.6.1z:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.6.1z1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios_xe:17.6.2:*:*:*:*:*:*:*

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