CVE-2021-23937

DNS proxy and possible amplification attack

HIGH
7.5
CVSS Score
Published: May 25, 2021 at 08:05 AM UTC
Updated: June 17, 2026 at 03:39 AM UTC
1 product affected across 1 vendorWicket

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Severity
HIGH7.5
Exploit prediction
EPSS 4%

Description

A DNS proxy and possible amplification attack vulnerability in WebClientInfo of Apache Wicket allows an attacker to trigger arbitrary DNS lookups from the server when the X-Forwarded-For header is not properly sanitized. This DNS lookup can be engineered to overload an internal DNS server or to slow down request processing of the Apache Wicket application causing a possible denial of service on either the internal infrastructure or the web application itself. This issue affects Apache Wicket Apache Wicket 9.x version 9.2.0 and prior versions; Apache Wicket 8.x version 8.11.0 and prior versions; Apache Wicket 7.x version 7.17.0 and prior versions and Apache Wicket 6.x version 6.2.0 and later versions.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.0.0 ≤ v ≤ 6.2.06.2.0 ≤ v < Apache Wicket 6.x*7.0.0 ≤ v ≤ 7.17.08.0.0 ≤ v ≤ 8.11.09.0.0 ≤ v ≤ 9.2.0Apache Wicket 7.x ≤ v ≤ 7.17.0Apache Wicket 8.x ≤ v ≤ 8.11.0Apache Wicket 9.x ≤ v ≤ 9.2.06.2.07.x8.x9.x
Affected range stops below Apache Wicket 6.x*, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-200

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