How severe is CVE-2021-1350?

CVE-2021-1350 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.

Is CVE-2021-1350 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-1350?

CVE-2021-1350 affects Cisco Umbrella. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-1350?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-1350 published?

CVE-2021-1350 was published on 2021-01-20 and last updated on 2026-06-17.

CVE-2021-1350

CVE-2021-1350 is a medium-severity vulnerability in Cisco Umbrella with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-770.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 5.0
EPSS exploit prediction: 1% (67th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-770
Affected product: Cisco Umbrella
Published: 2021-01-20
Last modified: 2026-06-17

Description

A vulnerability in the web UI of Cisco Umbrella could allow an unauthenticated, remote attacker to negatively affect the performance of this service. The vulnerability exists due to insufficient rate limiting controls in the web UI. An attacker could exploit this vulnerability by sending crafted HTTPS packets at a high and sustained rate. A successful exploit could allow the attacker to negatively affect the performance of the web UI. Cisco has addressed this vulnerability.

Frequently asked questions

What is CVE-2021-1350?: A vulnerability in the web UI of Cisco Umbrella could allow an unauthenticated, remote attacker to negatively affect the performance of this service. The vulnerability exists due to insufficient rate limiting controls in the web UI. An attacker could exploit this vulnerability by sending crafted HTTPS packets at a high and sustained rate. A successful exploit could allow the attacker to negatively affect the performance of the web UI. Cisco has addressed this vulnerability.
How severe is CVE-2021-1350?: CVE-2021-1350 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.
Is CVE-2021-1350 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-1350?: CVE-2021-1350 affects Cisco Umbrella. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-1350?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-1350 published?: CVE-2021-1350 was published on 2021-01-20 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-umb-dos-dgKzDEBP

Affected products (1)

cpe:2.3:a:cisco:umbrella:-:*:*:*:*:*:*:*

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