CVE-2021-45105 - CVE House
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Status published Unknown CVE-2021-45105

Apache Log4j2 does not always protect from infinite recursion in lookup evaluation

Vulnerability 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.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

The following person or organization is credited with identifying this vulnerability, as recorded in the NVD database:

  • Independently discovered by Hideki Okamoto of Akamai Technologies, Guy Lederfein of Trend Micro Research working with Trend Micro’s Zero Day Initiative, and another anonymous vulnerability researcher

Affected Vendor

Apache Software Foundation

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Affected Software

Apache Log4j2
Vulnerable Versions:
log4j-core

Timeline

Official Publish: December 18th, 2021
Last Modified: May 29th, 2026
Added to House: July 21st, 2026

CVSS Vectors

No vector data available

Weaknesses (CWE)