Vulnerability Report

CVE-2021-45046

RCE CISA KEV Active

Title: It was found that the fix to address CVE-2021-44228 in Apache Log4j 2.15.0 was incomplete in certain non-default configurations.

RCE

Proof Of Concept

PoC Available for CVE-2021-45046

CWE Category CWE-917
Published Date Dec 14, 2021
Modified Date Oct 27, 2025
Exploit Status Available
Score 9.0 CVSS v3.1
Exploit Probability (EPSS)
99.98%

Vulnerability Summary

CVE-2021-45046: 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.

Impacted Vendors

S
siemens 42
A
apache 1
C
cvat 1
N
netscape 1
W
websense 1
I
intel 9
C
cloudera 1
S
sonicwall 3
M
mendix 1

Reference Links

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://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EOKPQGV24RRBBI4TBZUDQMM4MEH7MXCY/ https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SIG7FZULMNK2XF6FZRU4VWYDQXNMUGAJ/ https://logging.apache.org/log4j/2.x/security.html 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-log4j-qRuKNEbd https://www.cve.org/CVERecord?id=CVE-2021-44228 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 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://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EOKPQGV24RRBBI4TBZUDQMM4MEH7MXCY/ https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SIG7FZULMNK2XF6FZRU4VWYDQXNMUGAJ/ https://logging.apache.org/log4j/2.x/security.html 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-log4j-qRuKNEbd https://www.cve.org/CVERecord?id=CVE-2021-44228 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 https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-45046
CVSS v3.1
Source Entity [email protected]
Severity CRITICAL
9.0
Attack Vector
NETWORK
Complexity
HIGH
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
CHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
CVSS v3.1
Source Entity 134c704f-9b21-4f2e-91b3-4a467353bcc0
Severity CRITICAL
9.0
Attack Vector
NETWORK
Complexity
HIGH
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
CHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
CVSS v2.0
Source Entity [email protected]
Severity MEDIUM
5.1
Access Vector
N/A
Authentication
N/A
RAW VECTOR AV:N/AC:H/Au:N/C:P/I:P/A:P

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2021-45046 Exploits & PoCs (Proof Of Concept)

GitHub https://github.com/NCSC-NL/log4shell
View Code
GitHub https://github.com/fox-it/log4j-finder
View Code
MODIFIED

Vulnerability data or affected products updated.

PUBLISHED

Vulnerability first announced in NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity HIGH
Privileges N/A
Interaction NONE
CVSS Vector String CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Affected Stack

No specific products linked.