--- id: CVE-2021-45046 aliases: - GHSA-7rjr-3q55-vv33 title: Incomplete fix for Apache Log4j vulnerability summary: Incomplete fix for Apache Log4j vulnerability severity: critical cvss: 9 cwe: - CWE-502 - CWE-917 vendor: apache product: 'org.apache.logging.log4j:log4j-core' ecosystem: maven affected: - 'org.apache.logging.log4j:log4j-core >= 2.13.0, < 2.16.0' - 'org.ops4j.pax.logging:pax-logging-log4j2 >= 1.8.0, < 1.9.2' - 'org.ops4j.pax.logging:pax-logging-log4j2 >= 1.10.0, < 1.10.8' - 'org.ops4j.pax.logging:pax-logging-log4j2 >= 1.11.0, < 1.11.11' - 'org.ops4j.pax.logging:pax-logging-log4j2 >= 2.0.0, < 2.0.12' - 'org.apache.logging.log4j:log4j-core >= 2.4.0, < 2.12.2' - 'org.apache.logging.log4j:log4j-core < 2.3.1' patched: - 'org.apache.logging.log4j:log4j-core 2.16.0' - 'org.ops4j.pax.logging:pax-logging-log4j2 1.9.2' - 'org.ops4j.pax.logging:pax-logging-log4j2 1.10.8' - 'org.ops4j.pax.logging:pax-logging-log4j2 1.11.11' - 'org.ops4j.pax.logging:pax-logging-log4j2 2.0.12' - 'org.apache.logging.log4j:log4j-core 2.12.2' - 'org.apache.logging.log4j:log4j-core 2.3.1' published: '2021-12-14' updated: '2026-10-02' sourceUpdated: '2026-10-02T20:21:54Z' source: GHSA sourceUrl: 'https://github.com/advisories/GHSA-7rjr-3q55-vv33' references: - url: 'https://nvd.nist.gov/vuln/detail/CVE-2021-45046' - url: 'https://logging.apache.org/log4j/2.x/security.html' - url: 'https://www.openwall.com/lists/oss-security/2021/12/14/4' - url: 'https://www.cve.org/CVERecord?id=CVE-2021-44228' - url: >- https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00646.html - url: 'https://cert-portal.siemens.com/productcert/pdf/ssa-661247.pdf' - url: 'https://cert-portal.siemens.com/productcert/pdf/ssa-714170.pdf' - url: 'https://www.kb.cert.org/vuls/id/930724' - url: 'https://www.debian.org/security/2021/dsa-5022' - url: 'https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0032' - url: 'https://www.oracle.com/security-alerts/alert-cve-2021-44228.html' - url: 'https://cert-portal.siemens.com/productcert/pdf/ssa-397453.pdf' - url: 'https://cert-portal.siemens.com/productcert/pdf/ssa-479842.pdf' - url: 'https://www.oracle.com/security-alerts/cpujan2022.html' - url: 'https://www.oracle.com/security-alerts/cpuapr2022.html' - url: 'https://www.oracle.com/security-alerts/cpujul2022.html' - url: 'https://security.gentoo.org/glsa/202310-16' - url: >- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/SIG7FZULMNK2XF6FZRU4VWYDQXNMUGAJ - url: >- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/EOKPQGV24RRBBI4TBZUDQMM4MEH7MXCY - url: >- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-log4j-qRuKNEbd - url: >- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-45046 - url: 'https://www.openwall.com/lists/oss-security/2021/12/18/1' - url: 'https://www.openwall.com/lists/oss-security/2021/12/15/3' - url: 'https://logging.apache.org/security.html#CVE-2021-45046' - url: 'https://github.com/apache/logging-log4j2/compare/rel/2.3...rel/2.3.1' - url: 'https://github.com/advisories/GHSA-7rjr-3q55-vv33' tags: - ghsa - maven - kev - in-the-wild - exploit-available epss: 0.99977 epssPercentile: 0.9998 kev: true kevDateAdded: '2023-05-01' kevDueDate: '2023-05-22' kevRansomware: true exploited: true exploits: github: 11 githubRepos: - 'https://github.com/cckuailong/Log4j_CVE-2021-45046' - 'https://github.com/BobTheShoplifter/CVE-2021-45046-Info' - 'https://github.com/tejas-nagchandi/CVE-2021-45046' metasploit: - auxiliary/scanner/http/log4shell_scanner nuclei: - CVE-2021-45046 checkedAt: '2026-10-02T22:33:43.920Z' exploitAvailable: true ingestedAt: '2026-10-02T22:33:09.854Z' --- ## Overview # Impact The fix to address [CVE-2021-44228](https://nvd.nist.gov/vuln/detail/CVE-2021-44228) in Apache Log4j 2.15.0 was incomplete in certain non-default configurations. This could allow 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 a remote code execution (RCE) attack. ## Affected packages Only the `org.apache.logging.log4j:log4j-core` package is directly affected by this vulnerability. The `org.apache.logging.log4j:log4j-api` should be kept at the same version as the `org.apache.logging.log4j:log4j-core` package to ensure compatability if in use. # Mitigation Log4j 2.16.0 fixes this issue by removing support for message lookup patterns and disabling JNDI functionality by default. This issue can be mitigated in prior releases (< 2.16.0) by removing the JndiLookup class from the classpath (example: zip -q -d log4j-core-*.jar org/apache/logging/log4j/core/lookup/JndiLookup.class). Log4j 2.15.0 restricts JNDI LDAP lookups to localhost by default. Note that previous mitigations involving configuration such as to set the system property `log4j2.formatMsgNoLookups` to `true` do NOT mitigate this specific vulnerability. ## Affected packages - `org.apache.logging.log4j:log4j-core >= 2.13.0, < 2.16.0` - `org.ops4j.pax.logging:pax-logging-log4j2 >= 1.8.0, < 1.9.2` - `org.ops4j.pax.logging:pax-logging-log4j2 >= 1.10.0, < 1.10.8` - `org.ops4j.pax.logging:pax-logging-log4j2 >= 1.11.0, < 1.11.11` - `org.ops4j.pax.logging:pax-logging-log4j2 >= 2.0.0, < 2.0.12` - `org.apache.logging.log4j:log4j-core >= 2.4.0, < 2.12.2` - `org.apache.logging.log4j:log4j-core < 2.3.1` ## Remediation Upgrade to a patched release: - `org.apache.logging.log4j:log4j-core 2.16.0` - `org.ops4j.pax.logging:pax-logging-log4j2 1.9.2` - `org.ops4j.pax.logging:pax-logging-log4j2 1.10.8` - `org.ops4j.pax.logging:pax-logging-log4j2 1.11.11` - `org.ops4j.pax.logging:pax-logging-log4j2 2.0.12` - `org.apache.logging.log4j:log4j-core 2.12.2` - `org.apache.logging.log4j:log4j-core 2.3.1`