CVE-2024-20406

Cisco IOS XR Software Intermediate System-to-Intermediate System Denial of Service Vulnerability

Published Sep 11, 2024 CVSS 3.1 · 7.4 High EPSS < 1% KEV · Not listed

Description

A vulnerability in the segment routing feature for the Intermediate System-to-Intermediate System (IS-IS) protocol of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device.

This vulnerability is due to insufficient input validation of ingress IS-IS packets. An attacker could exploit this vulnerability by sending specific IS-IS packets to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the IS-IS process on all affected devices that are participating in the Flexible Algorithm to crash and restart, resulting in a 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 and must have formed an adjacency. This vulnerability affects segment routing for IS-IS over IPv4 and IPv6 control planes as well as devices that are configured as level 1, level 2, or multi-level routing IS-IS type.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Cisco

Cisco IOS XR Software

unknown

Version	Status	Constraints
`7.4.1`	affected	—
`6.8.1`	affected	—
`7.4.15`	affected	—
`7.5.1`	affected	—
`7.4.16`	affected	—
`7.6.1`	affected	—
`7.5.2`	affected	—
`7.8.1`	affected	—
`7.6.15`	affected	—
`7.5.12`	affected	—
`7.7.1`	affected	—
`6.8.2`	affected	—
`7.4.2`	affected	—
`6.9.1`	affected	—
`7.6.2`	affected	—
`7.5.3`	affected	—
`7.7.2`	affected	—
`6.9.2`	affected	—
`7.9.1`	affected	—
`7.10.1`	affected	—
`7.8.2`	affected	—
`7.5.4`	affected	—
`7.8.22`	affected	—
`7.7.21`	affected	—
`7.9.2`	affected	—
`7.5.5`	affected	—
`7.11.1`	affected	—
`7.9.21`	affected	—
`7.10.2`	affected	—
`7.6.3`	affected	—

Configuration 1 [-]

OR	cpe:2.3:o:cisco:ios_xr::::::::
	cpe:2.3:o:cisco:ios_xr::::::::

No data.

No data available yet.

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

Source	ID	Title
EUVD	EUVD-2024-18121	A vulnerability in the segment routing feature for the Intermediate System-to-Intermediate System (IS-IS) protocol of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient input validation of ingress IS-IS packets. An attacker could exploit this vulnerability by sending specific IS-IS packets to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the IS-IS process on all affected devices that are participating in the Flexible Algorithm to crash and restart, resulting in a 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 and must have formed an adjacency. This vulnerability affects segment routing for IS-IS over IPv4 and IPv6 control planes as well as devices that are configured as level 1, level 2, or multi-level routing IS-IS type.

Metrics

No CVSS v4.0

Attack Vector Adjacent Network

Attack Complexity Low

Privileges Required None

Scope Changed

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.238% probability within 30 days)

Exploitation none

Automatable no

Technical Impact partial

References

Link	Providers
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-isis-xehpbVNe

History

Oct 7, 2024 6:15 PM First appearance in the feed. Weaknesses updated. Affected versions updated. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Cisco Cisco ios Xr
Weaknesses		NVD-CWE-noinfo
CPEs		cpe:2.3:o:cisco:ios_xr::::::::
Vendors & Products		Cisco Cisco ios Xr

Sep 11, 2024 9:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Sep 11, 2024 5:00 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		A vulnerability in the segment routing feature for the Intermediate System-to-Intermediate System (IS-IS) protocol of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient input validation of ingress IS-IS packets. An attacker could exploit this vulnerability by sending specific IS-IS packets to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the IS-IS process on all affected devices that are participating in the Flexible Algorithm to crash and restart, resulting in a 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 and must have formed an adjacency. This vulnerability affects segment routing for IS-IS over IPv4 and IPv6 control planes as well as devices that are configured as level 1, level 2, or multi-level routing IS-IS type.
Title		Cisco IOS XR Software Intermediate System-to-Intermediate System Denial of Service Vulnerability
Weaknesses		CWE-20
References		https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-isis-xehpbVNe
Metrics		cvssV3_1 `{'score': 7.4, 'vector': 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H'}`