CVE-2024-20317 [High] | Denial of Service in Ios Xr

A vulnerability in the handling of specific Ethernet frames by Cisco IOS XR Software for various Cisco Network Convergence System (NCS) platforms could allow an unauthenticated, adjacent attacker to cause critical priority packets to be dropped, resulting in a denial of service (DoS) condition. This vulnerability is due to incorrect classification of certain types of Ethernet frames that are received on an interface. An attacker could exploit this vulnerability by sending specific types of Ethernet frames to or through the affected device. A successful exploit could allow the attacker to cause control plane protocol relationships to fail, resulting in a DoS condition. For more information, see the section of this advisory. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-03-16	0.29%	0.22%	-0.07%
2	2026-03-14	0.19%	0.29%	+0.10%
3	2025-11-21	—	0.19%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-03-16

0.29%

0.22%

-0.07%

2026-03-14

0.19%

0.29%

+0.10%

2025-11-21

—

0.19%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
7.4	3.1	HIGH	`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H` Click to expand Attack vector (AV:A) Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	2.8	4.0	[email protected]
7.4	3.1	HIGH	`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H` Click to expand Attack vector (AV:A) Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	2.8	4.0	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

7.4

3.1

HIGH

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H Click to expand

Attack vector (AV:A): Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

2.8

4.0

[email protected]

7.4

3.1

HIGH

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H Click to expand

Attack vector (AV:A): Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

2.8

4.0

[email protected]

Affected software / configurations for CVE-2024-20317

Vendor	Product	Version	Raw CPE
cisco	ios_xr	7.7.1	cpe:2.3:o:cisco:ios_xr:7.7.1:::::::*
cisco	ios_xr	7.7.2	cpe:2.3:o:cisco:ios_xr:7.7.2:::::::*
cisco	ios_xr	7.7.21	cpe:2.3:o:cisco:ios_xr:7.7.21:::::::*
cisco	ios_xr	7.8.1	cpe:2.3:o:cisco:ios_xr:7.8.1:::::::*
cisco	ios_xr	7.8.2	cpe:2.3:o:cisco:ios_xr:7.8.2:::::::*
cisco	ios_xr	7.8.22	cpe:2.3:o:cisco:ios_xr:7.8.22:::::::*
cisco	ios_xr	7.9.1	cpe:2.3:o:cisco:ios_xr:7.9.1:::::::*
cisco	ios_xr	7.9.2	cpe:2.3:o:cisco:ios_xr:7.9.2:::::::*
cisco	ios_xr	7.9.21	cpe:2.3:o:cisco:ios_xr:7.9.21:::::::*
cisco	ios_xr	7.10.1	cpe:2.3:o:cisco:ios_xr:7.10.1:::::::*

References for CVE-2024-20317

URL	Tags
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-l2services-2mvHdNuC	Vendor Advisory

URL

CVE-2024-20317 | Cisco IOS XR Software Layer 2 Services Denial of Service Vulnerability

Exploit prediction scoring system (EPSS) score for CVE-2024-20317

Common vulnerability scoring system (CVSS) metrics for CVE-2024-20317

Weakness enumeration for CVE-2024-20317

Affected software / configurations for CVE-2024-20317

References for CVE-2024-20317