CVE-2021-45105
Apache Log4j2 does not always protect from infinite recursion in lookup evaluation
- State
- Published
- Severity
- 5.9 Medium
- Published
- Dec 18, 2021
- Updated
- May 29, 2026
- Reserved
- Dec 16, 2021
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 5.9 Medium | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H | CISA-ADP |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
Apache Log4j2Apache Software Foundation |
|
References
- https://logging.apache.org/log4j/2.x/security.html
- https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0032
- VU#930724third-party-advisory
- 20211210 Vulnerabilities in Apache Log4j Library Affecting Cisco Products: December 2021vendor-advisory
- [oss-security] 20211218 CVE-2021-45105: Apache Log4j2 does not always protect from infinite recursion in lookup evaluationmailing-list
- DSA-5024vendor-advisory
- https://cert-portal.siemens.com/productcert/pdf/ssa-479842.pdf
- https://security.netapp.com/advisory/ntap-20211218-0001/
- https://www.zerodayinitiative.com/advisories/ZDI-21-1541/
- https://cert-portal.siemens.com/productcert/pdf/ssa-501673.pdf
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://www.oracle.com/security-alerts/cpujul2022.html
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.