Cisco SD-WAN Buffer Overflow Vulnerabilities

published 2021-01-20 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-6768

cvss: 9.8; version 3.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 2.1%; EPSS 2.1% chance of exploitation in 30 days, percentile 82%
public exploits: 0; none known

Multiple vulnerabilities in Cisco SD-WAN products could allow an unauthenticated, remote attacker to execute attacks against an affected device. For more information about these vulnerabilities, see the Details section of this advisory.

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: total
Assessed: 2 y ago (2024-11-08)

Exploit prediction

2.13% chance of exploitation in the next 30 days, higher than 82% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.0	9.8	CVSS:3.0/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	7.5	AV:N/AC:L/Au:N/C:P/I:P/A:P

Affected products

Cisco Cisco SD-WAN Solution

Classification

Weakness

CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-20 Improper Input Validation

References

tools.cisco.com /security/center/content/CiscoSecurityAdvisory/cisco-sa-sdwan-bufovulns-B5NrSHbj
vendor-advisory

Sources

CVE List CVE-2021-1301
NVD CVE-2021-1301

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary