How severe is CVE-2024-20266?

CVE-2024-20266 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.

Is CVE-2024-20266 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2024-20266?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2024-20266 have an EU (EUVD) identifier?

Yes. CVE-2024-20266 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-17981.

When was CVE-2024-20266 published?

CVE-2024-20266 was published on 2024-03-13 and last updated on 2026-06-17.

CVE-2024-20266

CVE-2024-20266 is a medium-severity vulnerability with a CVSS 3.x base score of 5.3. 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: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 1% (46th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2024-17981
Weakness: CWE-476
Published: 2024-03-13
Last modified: 2026-06-17

Description

A vulnerability in the DHCP version 4 (DHCPv4) server feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to trigger a crash of the dhcpd process, resulting in a denial of service (DoS) condition. This vulnerability exists because certain DHCPv4 messages are improperly validated when they are processed by an affected device. An attacker could exploit this vulnerability by sending a malformed DHCPv4 message to an affected device. A successful exploit could allow the attacker to cause a crash of the dhcpd process. While the dhcpd process is restarting, which may take approximately two minutes, DHCPv4 server services are unavailable on the affected device. This could temporarily prevent network access to clients that join the network during that time period and rely on the DHCPv4 server of the affected device. Notes: Only the dhcpd process crashes and eventually restarts automatically. The router does not reload. This vulnerability only applies to DHCPv4. DHCP version 6 (DHCPv6) is not affected.

Frequently asked questions

What is CVE-2024-20266?: A vulnerability in the DHCP version 4 (DHCPv4) server feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to trigger a crash of the dhcpd process, resulting in a denial of service (DoS) condition. This vulnerability exists because certain DHCPv4 messages are improperly validated when they are processed by an affected device. An attacker could exploit this vulnerability by sending a malformed DHCPv4 message to an affected device. A successful exploit could allow the attacker to cause a crash of the dhcpd process. While the dhcpd process is restarting, which may take approximately two minutes, DHCPv4 server services are unavailable on the affected device. This could temporarily prevent network access to clients that join the network during that time period and rely on the DHCPv4 server of the affected device. Notes: Only the dhcpd process crashes and eventually restarts automatically. The router does not reload. This vulnerability only applies to DHCPv4. DHCP version 6 (DHCPv6) is not affected.
How severe is CVE-2024-20266?: CVE-2024-20266 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.
Is CVE-2024-20266 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2024-20266?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2024-20266 have an EU (EUVD) identifier?: Yes. CVE-2024-20266 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-17981.
When was CVE-2024-20266 published?: CVE-2024-20266 was published on 2024-03-13 and last updated on 2026-06-17.

References

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-dhcp-dos-3tgPKRdm

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