CVE-2021-34727 json
Cisco IOS XE SD-WAN Software Buffer Overflow Vulnerability
published 2021-09-23 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-21377
- cvss
- 9.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 2.6%
- EPSS 2.6% chance of exploitation in 30 days, percentile 85%
- public exploits
- 0
- none known
Summary
A vulnerability in the vDaemon process in Cisco IOS XE SD-WAN Software could allow an unauthenticated, remote attacker to cause a buffer overflow on an affected device. This vulnerability is due to insufficient bounds checking when an affected device processes traffic. An attacker could exploit this vulnerability by sending crafted traffic to the device. A successful exploit could allow the attacker to cause a buffer overflow and possibly execute arbitrary commands with root-level privileges, or cause the device to reload, which could result in a denial of service condition.
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- total
- Assessed
- 2 y ago
Exploit prediction
2.63% chance of exploitation in the next 30 days, higher than 85% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVD | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVD | 2.0 | 10.0 | AV:N/AC:L/Au:N/C:C/I:C/A:C |
Affected products
- Cisco Cisco IOS XE SD-WAN Software
Classification
- Weakness
-
- CWE-120 Buffer Copy without Checking Size of Input
References
Sources
- CVE List CVE-2021-34727
- NVD CVE-2021-34727
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