How severe is CVE-2020-3246?

CVE-2020-3246 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2020-3246 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (55th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-3246?

CVE-2020-3246 affects Cisco Umbrella. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-3246?

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

When was CVE-2020-3246 published?

CVE-2020-3246 was published on 2020-05-06 and last updated on 2026-06-17.

CVE-2020-3246

CVE-2020-3246 is a medium-severity vulnerability in Cisco Umbrella with a CVSS 3.x base score of 4.3. 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-74.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
CVSS v2: 4.3
EPSS exploit prediction: 1% (55th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-74
Affected product: Cisco Umbrella
Published: 2020-05-06
Last modified: 2026-06-17

Description

A vulnerability in the web server of Cisco Umbrella could allow an unauthenticated, remote attacker to perform a carriage return line feed (CRLF) injection attack against a user of an affected service. The vulnerability is due to insufficient validation of user input. An attacker could exploit this vulnerability by persuading a user to access a crafted URL. A successful exploit could allow the attacker to inject arbitrary HTTP headers into valid HTTP responses sent to the browser of the user.

Frequently asked questions

What is CVE-2020-3246?: A vulnerability in the web server of Cisco Umbrella could allow an unauthenticated, remote attacker to perform a carriage return line feed (CRLF) injection attack against a user of an affected service. The vulnerability is due to insufficient validation of user input. An attacker could exploit this vulnerability by persuading a user to access a crafted URL. A successful exploit could allow the attacker to inject arbitrary HTTP headers into valid HTTP responses sent to the browser of the user.
How severe is CVE-2020-3246?: CVE-2020-3246 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2020-3246 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (55th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-3246?: CVE-2020-3246 affects Cisco Umbrella. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-3246?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-3246 published?: CVE-2020-3246 was published on 2020-05-06 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-umbrella-head-inject-n4QArJH

Affected products (1)

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

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