CVE-2025-20241

highpriority · track · 0EPSS 0.003 · 20 %ileDEEUNLRUUS
grimoire priorityP2 · Scheduled
Exploitable?
—
no known exploitation
Likely / severe?
0.28% (20th) EPSS
CVSS 7.4 · high
Is it mine?
487 products
Check your exposure
Who says so?
6 sources
cnnvd · enisa_euvd · fstec_bdu · cert_bund

EPSS · scored 2026-10-27

A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) feature of Cisco NX-OS Software for Cisco Nexus 3000 Series Switches and Cisco Nexus 9000 Series Switches in standalone NX-OS mode could allow an unauthenticated, adjacent attacker to cause the IS-IS process to unexpectedly restart, which could cause an affected device to reload. This vulnerability is due to insufficient input validation when parsing an ingress IS-IS packet. An attacker could exploit this vulnerability by sending a crafted IS-IS packet to an affected device. A successful exploit could allow the attacker to cause the unexpected restart of the IS-IS process, which could cause the affected device to reload, resulting in a denial of service (DoS) condition. Note: The IS-IS protocol is a routing protocol. To exploit this vulnerability, an attacker must be Layer 2-adjacent to the affected device.

01

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

02

cvss

Technical severity, 0–10. One row per scoring source.

7.4
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.8–7.4

v3.17.4highAV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · FSTEC (BDU) RU
v3.17.4highCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · ENISA EU
v3.17.4highCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · psirt@cisco.com USexploitability 2.8 · impact 4
v3.16.8mediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)
v3.17.4highCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · NCSC-NL NL
v3.17.4highCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · Cisco PSIRT US
03

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS
04

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-733USCWE-733USCWE-733US
05

affected products (487)

Products and version ranges known to be affected.

showing 20 of 487
06

advisories (4)

Vendor and ecosystem advisories describing this.

  • NCSC-2025-0270Kwetsbaarheden verholpen in Cisco NX-OS SoftwareNL2025-08-28csaf · ncsc_nlNL

    Cisco heeft kwetsbaarheden verholpen in Cisco NX-OS Software (Specifiek voor Nexus 3000 en 9000 Series Switches).

  • NCSC-2025-0287Kwetsbaarheden verholpen in Cisco NX-OS SoftwareNL2025-09-11csaf · ncsc_nlNL

    Cisco heeft kwetsbaarheden verholpen in Cisco NX-OS Software voor Nexus 3000 en 9000 Series Switches.

  • WID-SEC-W-2025-1915Cisco Nexus, Dashboard, NX-OS: Mehrere SchwachstellenDeutsch2025-08-27csaf · cert_bundDE

    Ein Angreifer kann mehrere Schwachstellen in Cisco Nexus, Cisco NX-OS, Cisco Unified Computing System (UCS) und Cisco Nexus Dashboard ausnutzen, um einen Denial-of-Service-Zustand zu erzeugen, Root-Rechte zu erlangen, vertrauliche Informationen offenzulegen und Daten zu manipulieren.

  • cisco-sa-n39k-isis-dos-JhJA8RfxCisco Nexus 3000 and 9000 Series Switches Intermediate System-to-Intermediate System Denial of Service Vulnerability2025-08-27csaf · cisco_csafUS

    A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) feature of Cisco NX-OS Software for Cisco Nexus 3000 Series Switches and Cisco Nexus 9000 Series Switches in standalone NX-OS mode could allow an unauthenticated, adjacent attacker to cause the IS-IS process to unexpectedly restart, which could cause an affected device to reload. This vulnerability is due to insufficient input validation when parsing an ingress IS-IS packet. An attacker could exploit this vulnerability by sending a crafted IS-IS packet to an affected device. A successful exploit could allow the attacker to cause the unexpected restart of the IS-IS process, which could cause the affected device to reload, resulting in a denial of service (DoS) condition. Note: The IS-IS protocol is a routing protocol. To exploit this vulnerability, an attacker must be Layer 2-adjacent to the affected device. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is part of the August 2025 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: August 2025 Semiannual Cisco FXOS and NX-OS Software Security Advisory Bundled Publication ["https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-75667"].

07

also known as (4)

Other names and identifiers for this entity.

08

sources

Which sources assert this record, and when.

cnnvdenisa_euvdfstec_bducert_bundcisco_csafncsc_nlNVDCVE.orgMITRE
published 2025-08-27modified 2026-06-17
09

references (5)

External citations — patches, advisories, analysis.

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