CVE-2021-45046
Apache Log4j2 Thread Context Message Pattern and Context Lookup Pattern vulnerable to a denial of service attack
It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allows attackers with control over Thread Context Map (MDC) input data when the logging configuration uses a non-default Pattern Layout with either a Context Lookup (for example, $${ctx:loginId}) or a Thread Context Map pattern (%X, %mdc, or %MDC) to craft malicious input data using a JNDI Lookup pattern resulting in an information leak and remote code execution in some environments and local code execution in all environments. Log4j 2.16.0 (Java 8) and 2.12.2 (Java 7) fix this issue by removing support for message lookup patterns and disabling JNDI functionality by default.
- Affected
- Apache Software Foundation · Apache Log4j
- CVSS v3.1 NVD
- 9.0 CRITICAL
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H - CVSS v2.0 NVD
- 5.1 MEDIUM
AV:N/AC:H/Au:N/C:P/I:P/A:P - EPSS
- 99.98% chance of exploitation in the next 30 days, 100th percentile
- CISA KEV
- added 2023-05-01, used in ransomware campaigns
- Nuclei
- critical · CWE-917
- Published
- 2021-12-14
- Updated
- 2025-10-21
Proof-of-concept exploits (14)
- BobTheShoplifter/CVE-2021-45046-Info4★ · 2022-04-07
- EMSeek/log4poc1★ · 2021-12-20
- Puliczek/CVE-2021-44228-PoC-log4j-bypass-words950★ · 2022-01-15
- VMsec/log4jScan_Modify3★ · 2022-01-14
- cckuailong/Log4j_CVE-2021-4504622★ · 2021-12-23
- hbeooooooom/Log4shell_poc1★ · 2025-01-02
- ifconfig-me/Log4Shell-Payloads8★ · 2025-07-23
- ludy-dev/cve-2021-450461★ · 2021-12-18
- lwollan/log4j-exploit-server0★ · 2022-03-28
- pravin-pp/log4j2-CVE-2021-450460★ · 2021-12-15
- shaily29-eng/CyberSecurity_CVE-2021-450460★ · 2024-05-21
- sschakraborty/SecurityPOC1★ · 2023-03-07
- tejas-nagchandi/CVE-2021-450460★ · 2021-12-16
- yonocruzhj/AIG---Tasks0★ · 2024-12-21
Nuclei templates (1)
Security advisories
- https://logging.apache.org/log4j/2.x/security.html
- http://www.openwall.com/lists/oss-security/2021/12/14/4
- http://www.openwall.com/lists/oss-security/2021/12/15/3
- http://www.openwall.com/lists/oss-security/2021/12/18/1
- https://cert-portal.siemens.com/productcert/pdf/ssa-397453.pdf
- https://cert-portal.siemens.com/productcert/pdf/ssa-479842.pdf
- https://cert-portal.siemens.com/productcert/pdf/ssa-661247.pdf
- https://cert-portal.siemens.com/productcert/pdf/ssa-714170.pdf
- https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0032
- https://security.gentoo.org/glsa/202310-16
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-log…
- https://www.debian.org/security/2021/dsa-5022
- https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00646.html
- https://www.kb.cert.org/vuls/id/930724
- https://www.oracle.com/security-alerts/alert-cve-2021-44228.html
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://www.oracle.com/security-alerts/cpujul2022.html
- advisories/GHSA-7rjr-3q55-vv33
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/…
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/…