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CVE-2020-3246

Cisco Umbrella Carriage Return Line Feed Injection Vulnerability

4.7 Medium

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
Required

What an attacker can affect

Confidentiality
None
Integrity
Low
Availability
None

Exploit likelihood

0.90%Up 0.3 points since Apr 14, 2021
90%50%10%1%

What each source reports

CVE List Score used 4.7

Cisco Umbrella Carriage Return Line Feed Injection Vulnerability

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.

Record
CVE-2020-3246
CVSS 3.0
4.7 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N
Weakness
CWE-93
Updated
2026-11-02
EUVDEUVD-2020-24517 4.7

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.

Record
EUVD-2020-24517
CVSS 3.0
4.7 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N
Updated
2026-11-03
GitHub AdvisoriesGHSA-j53q-vx25-fmqm No score

A vulnerability in the web server of Cisco Umbrella could allow an unauthenticated, remote...

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.

Record
GHSA-j53q-vx25-fmqm
Updated
2026-11-02
NVD 4.3

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.

Record
CVE-2020-3246
CVSS 3.1
4.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
CVSS 3.0
4.7 MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N
CVSS 2.0
4.3 MediumAV:N/AC:M/Au:N/C:N/I:P/A:N
Weakness
CWE-93, CWE-74
Updated
2026-11-02

Affected products

History

History
RecordedChangedSources
aliases, publishedEUVD
first indexedCVE List, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2020-3246 is a medium vulnerability (CVSS 4.7) in Cisco Umbrella, published May 6, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.90%, the 59th percentile. No source names a fixed version.

References

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