TI-2021-01334 Aliases CVE-2021-1611 GHSA-4xpj-f87g-q66q

Cisco IOS XE Software for Catalyst 9800 Series Wireless Controllers EoGRE Denial of Service Vulnerability

MEDIUM 48CWE-399Published 2021-09-23 · Updated 2024-11-07

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: No fix listed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-399 and the CVSS impact.

Summary

A vulnerability in Ethernet over GRE (EoGRE) packet processing of Cisco IOS XE Wireless Controller Software for the Cisco Catalyst 9800 Family Wireless Controller, Embedded Wireless Controller, and Embedded Wireless on Catalyst 9000 Series Switches could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper processing of malformed EoGRE packets. An attacker could exploit this vulnerability by sending malicious packets to the affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.01328 71st percentileScored 2026-11-07

Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Cisco	Cisco IOS XE Software	all versions	—	No fix listed	CNA

Cisco IOS XE Software VendorCisco Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 8

CPE	Versions	Role	Vendor
cpe:2.3:o:cisco:ios_xe::::::::	before 17.3.1	Vulnerable	Cisco
cpe:2.3:h:cisco:catalyst_9800:-:::::::*	not specified by NVD	Running on	Cisco
cpe:2.3:h:cisco:catalyst_9800-40:-:::::::*	not specified by NVD	Running on	Cisco
cpe:2.3:h:cisco:catalyst_9800-80:-:::::::*	not specified by NVD	Running on	Cisco
cpe:2.3:h:cisco:catalyst_9800-cl:-:::::::*	not specified by NVD	Running on	Cisco
cpe:2.3:h:cisco:catalyst_9800-l:-:::::::*	not specified by NVD	Running on	Cisco
cpe:2.3:h:cisco:catalyst_9800-l-c:-:::::::*	not specified by NVD	Running on	Cisco
cpe:2.3:h:cisco:catalyst_9800-l-f:-:::::::*	not specified by NVD	Running on	Cisco

cpe:2.3:o:cisco:ios_xe:*:*:*:*:*:*:*:* Versions before 17.3.1 Vulnerable ·Cisco
cpe:2.3:h:cisco:catalyst_9800:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
cpe:2.3:h:cisco:catalyst_9800-40:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
cpe:2.3:h:cisco:catalyst_9800-80:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
cpe:2.3:h:cisco:catalyst_9800-cl:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
cpe:2.3:h:cisco:catalyst_9800-l:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
cpe:2.3:h:cisco:catalyst_9800-l-c:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco
cpe:2.3:h:cisco:catalyst_9800-l-f:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Cisco

Remediation

No fixed version listed by the sources yet.

Timeline

2026-10-02 Threatist record created from CVE-2021-1611
2026-10-03 Alias added: GHSA-4xpj-f87g-q66q

References

Patch 1

20210922 Cisco IOS XE Software for Catalyst 9800 Series Wireless Controllers EoGRE Denial of Service Vulnerability

TI-2023-06904 Cisco is providing an update for the ongoing investigation into observed exploitation of… KEVCVSS 3.1CRITICAL 10.0
TI-2018-00122 Memory corruption in Cisco IOS and IOS XE KEVCVSS 3.1CRITICAL 9.8
TI-2017-02977 Improper input validation in Cisco IOS and IOS XE Software KEVCVSS 3.1CRITICAL 9.8
TI-2018-00135 Memory corruption in Cisco IOS, IOS XE, and IOS XR KEVCVSS 3.1HIGH 8.8
TI-2017-04498 Memory corruption in Cisco IOS KEVCVSS 3.1HIGH 8.8
TI-2017-04497 Memory corruption in Cisco IOS XE Software KEVCVSS 3.1HIGH 8.8

See all 561 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences