{"id":"CVE-2021-45105","aliases":["GHSA-p6xc-xr62-6r2g"],"url":"https://o3.security/vulnerability/CVE-2021-45105","summary":"Apache Log4j2 vulnerable to Improper Input Validation and Uncontrolled Recursion","details":"Apache Log4j2 versions 2.0-alpha1 through 2.16.0 (excluding 2.12.3) 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 and 2.12.3.\n\n\n# Affected packages\nOnly 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.","published":"2021-12-18T12:15:07.433Z","modified":"2026-10-20T10:55:07.720134174Z","cvss":{"score":5.9,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":{"score":0.99999,"percentile":0.99991,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":4,"affectedPackages":[{"ecosystem":"Maven","name":"org.apache.logging.log4j:log4j-core","fixedVersion":"2.12.3"},{"ecosystem":"Maven","name":"org.apache.logging.log4j:log4j-core","fixedVersion":"2.17.0"},{"ecosystem":"Maven","name":"org.apache.logging.log4j:log4j-core","fixedVersion":"2.3.1"},{"ecosystem":"Maven","name":"org.ops4j.pax.logging:pax-logging-log4j2","fixedVersion":"1.9.2"},{"ecosystem":"Maven","name":"org.ops4j.pax.logging:pax-logging-log4j2","fixedVersion":"1.10.9"},{"ecosystem":"Maven","name":"org.ops4j.pax.logging:pax-logging-log4j2","fixedVersion":"1.11.12"},{"ecosystem":"Maven","name":"org.ops4j.pax.logging:pax-logging-log4j2","fixedVersion":"2.0.13"}],"fix":null,"references":[{"type":"ADVISORY","url":"http://www.openwall.com/lists/oss-security/2021/12/19/1"},{"type":"ADVISORY","url":"https://cert-portal.siemens.com/productcert/pdf/ssa-479842.pdf"},{"type":"ADVISORY","url":"https://cert-portal.siemens.com/productcert/pdf/ssa-501673.pdf"},{"type":"ADVISORY","url":"https://logging.apache.org/log4j/2.x/security.html"},{"type":"ADVISORY","url":"https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0032"},{"type":"ADVISORY","url":"https://security.netapp.com/advisory/ntap-20211218-0001/"},{"type":"ADVISORY","url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-log4j-qRuKNEbd"},{"type":"ADVISORY","url":"https://www.debian.org/security/2021/dsa-5024"},{"type":"ADVISORY","url":"https://www.kb.cert.org/vuls/id/930724"},{"type":"ADVISORY","url":"https://www.oracle.com/security-alerts/cpujul2022.html"},{"type":"ADVISORY","url":"https://www.zerodayinitiative.com/advisories/ZDI-21-1541/"},{"type":"FIX","url":"https://www.oracle.com/security-alerts/cpuapr2022.html"},{"type":"FIX","url":"https://www.oracle.com/security-alerts/cpujan2022.html"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-45105"},{"type":"WEB","url":"https://www.zerodayinitiative.com/advisories/ZDI-21-1541"},{"type":"WEB","url":"https://security.netapp.com/advisory/ntap-20211218-0001"},{"type":"WEB","url":"https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-log4j-qRuKNEbd"},{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/SIG7FZULMNK2XF6FZRU4VWYDQXNMUGAJ"},{"type":"WEB","url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/EOKPQGV24RRBBI4TBZUDQMM4MEH7MXCY"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2021/12/msg00017.html"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-20T10:55:07.720134174Z"}}