CVE-2020-3337Network attack vector

User redirection via unvalidated URL parameters

Published Jun 18, 2020 · Updated Nov 15, 2024

Open redirect in the Cisco Umbrella web server allows remote attackers to send users to malicious websites through crafted HTTP requests. The server insufficiently validates attacker-controlled URL parameters and uses the supplied destination when redirecting the request. Exploitation requires user interaction; the documented effect is redirection to an attacker-chosen site, not data access or service interruption.

CVSS severity4.7
Medium
EPSS probability0.81%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Open redirect in the Cisco Umbrella web server allows remote attackers to send users to malicious websites through crafted HTTP requests. The server insufficiently validates attacker-controlled URL parameters and uses the supplied destination when redirecting the request. Exploitation requires user interaction; the documented effect is redirection to an attacker-chosen site, not data access or service interruption.

The record

CVE
CVE-2020-3337
Published
Jun 18, 2020
Updated
Nov 15, 2024
Vendor
Cisco Systems, Inc.
Product
Cisco Umbrella
Classifications
CWE-601
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 18, 2020CVE publishedPublication date reported by the CVE source.
  2. Nov 15, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Cisco Systems, Inc. · Cisco Umbrellaversion=n/a

Published CVSS scores

4.7Cisco Systems, Inc.CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N/E:X/RL:X/RC:X
5.8NISTAV:N/AC:M/Au:N/C:P/I:P/A:N
6.1NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-601URL Redirection to Untrusted Site ('Open Redirect')

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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