CVE-2025-20191
CVE-2025-20191 is a high-severity vulnerability 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-805.
Key facts
- Severity: High (CVSS 3.x base score 7.4)
- EPSS exploit prediction: 0% (10th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2025-13915
- Weakness: CWE-805
- Published:
- Last modified:
Description
A vulnerability in the Switch Integrated Security Features (SISF) of Cisco IOS Software, Cisco IOS XE Software, Cisco NX-OS Software, and Cisco Wireless LAN Controller (WLC) AireOS Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to the incorrect handling of DHCPv6 packets. An attacker could exploit this vulnerability by sending a crafted DHCPv6 packet to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
Frequently asked questions
- What is CVE-2025-20191?
- A vulnerability in the Switch Integrated Security Features (SISF) of Cisco IOS Software, Cisco IOS XE Software, Cisco NX-OS Software, and Cisco Wireless LAN Controller (WLC) AireOS Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to the incorrect handling of DHCPv6 packets. An attacker could exploit this vulnerability by sending a crafted DHCPv6 packet to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
- How severe is CVE-2025-20191?
- CVE-2025-20191 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-2025-20191 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (10th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2025-20191?
- 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-2025-20191 have an EU (EUVD) identifier?
- Yes. CVE-2025-20191 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-13915.
- When was CVE-2025-20191 published?
- CVE-2025-20191 was published on 2025-05-07 and last updated on 2026-06-17.
References
Other CWE-805 vulnerabilities
- CVE-2020-14509 — Critical (CVSS 9.8): Multiple memory corruption vulnerabilities exist in CodeMeter (All versions prior to 7.10) where the packet parser…
- CVE-2025-20315 — High (CVSS 8.6): A vulnerability in the Network-Based Application Recognition (NBAR) feature of Cisco IOS XE Software could allow an…
- CVE-2026-53016 — High (CVSS 7.8): In the Linux kernel, the following vulnerability has been resolved: crypto: ccp - copy IV using skcipher…
- CVE-2025-38743 — High (CVSS 7.8): Dell iDRAC Service Module (iSM), versions prior to 6.0.3.0, contains a Buffer Access with Incorrect Length Value…
- CVE-2025-20175 — High (CVSS 7.7): A vulnerability in the SNMP subsystem of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated,…
- CVE-2025-20174 — High (CVSS 7.7): A vulnerability in the SNMP subsystem of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated,…