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CVE-2021-45105

MediumCVSS 5.9 / 10
Published Dec 18, 2021·Last modified Apr 16, 2026
Affected Components(0)

No affected components available

Description

Apache Log4j2 versions 2.0-alpha1 through 2.16.0 (excluding 2.12.3 and 2.3.1) did not protect from uncontrolled recursion from self-referential lookups. This allows an attacker with control over Thread Context Map data to cause a denial of service when a crafted string is interpreted. This issue was fixed in Log4j 2.17.0, 2.12.3, and 2.3.1.

Risk Scores
Base Score
5.9

The vulnerability can be exploited over the network without needing physical access. It is difficult for an attacker to exploit this vulnerability and may require special conditions. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the availability of the system.

Threat Intelligence
5.6

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
100.00%

The exploit probability is critical. The vulnerability is very likely to be exploited in the next 30 days.

Exploit
Proof of Concept

A proof of concept is available for this vulnerability (9 exploits found).

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