CVE-2021-34713 json
Cisco IOS XR Software for ASR 9000 Series Routers Denial of Service Vulnerability
published 2021-09-09 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-21363
- cvss
- 7.4
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 30%
- public exploits
- 0
- none known
Summary
A vulnerability in the Layer 2 punt code of Cisco IOS XR Software running on Cisco ASR 9000 Series Aggregation Services Routers could allow an unauthenticated, adjacent attacker to cause the affected line card to reboot. This vulnerability is due to incorrect handling of specific Ethernet frames that cause a spin loop that can make the network processors unresponsive. An attacker could exploit this vulnerability by sending specific types of Ethernet frames on the segment where the affected line cards are attached. A successful exploit could allow the attacker to cause the affected line card to reboot.
Patch / fix
- cisco ios_xr 6.6.3, 6.7.1, 7.0.2, 7.1.1
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 2 y ago
Exploit prediction
0.36% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 7.4 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H |
| NVD | 3.1 | 7.4 | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H |
| NVD | 2.0 | 6.1 | AV:A/AC:L/Au:N/C:N/I:N/A:C |
Affected products
- Cisco Cisco IOS XR Software
Classification
- Weakness
-
- CWE-399 Resource Management Errors
- Technology feeds
References
Sources
- CVE List CVE-2021-34713
- NVD CVE-2021-34713
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