{"cve":"CVE-2026-34481","nvd":{"published":"2026-04-10T16:16:31.663","modified":"2026-10-26T22:10:00.163","status":"Modified","description":"Apache Log4j's  JsonTemplateLayout https://logging.apache.org/log4j/2.x/manual/json-template-layout.html , in versions up to and including 2.25.3, produces invalid JSON output when log events contain non-finite floating-point values (NaN, Infinity, or -Infinity), which are prohibited by RFC 8259. This may cause downstream log processing systems to reject or fail to index affected records.\n\nAn attacker can exploit this issue only if both of the following conditions are met:\n\n  *  The application uses JsonTemplateLayout.\n  *  The application logs a MapMessage, or logs an object directly (e.g., via Logger.info(Object), which wraps it in an ObjectMessage), where the message contains an attacker-controlled floating-point value.\n\n\nUsers are advised to upgrade to Apache Log4j JSON Template Layout 2.25.4, which corrects this issue.\n\nNote: The fix released in version 2.25.4 did not cover all affected code paths. CVE-2026-49844 was assigned to the remaining issue, which concerns the MapMessage.asJson() serialization in Apache Log4j API and is fixed in versions 2.25.5 and 2.26.1.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N","score":6.3},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","score":7.5},"cwes":["CWE-116"],"references":["https://github.com/apache/logging-log4j2/pull/4080","https://lists.apache.org/thread/n34zdv00gbkdbzt2rx9rf5mqz6lhopcv","https://logging.apache.org/cyclonedx/vdr.xml","https://logging.apache.org/log4j/2.x/manual/json-template-layout.html","https://logging.apache.org/security.html#CVE-2026-34481"],"products":["apache:log4j"],"source":"nvd","synced_at":"2026-10-26T22:26:44.656832877+00:00"},"epss":{"cve":"CVE-2026-34481","score":0.00691,"percentile":0.52551,"date":"2026-10-26"},"kev":null,"osv":[{"id":"GHSA-w35j-pv5h-q9q9","url":"https://osv.dev/vulnerability/GHSA-w35j-pv5h-q9q9","summary":"Apache Log4j JSON Template Layout: Improper serialization of non-finite floating-point values in JsonTemplateLayout","modified":"2026-09-10T03:51:03.622660398Z","packages":[{"ecosystem":"Maven","name":"org.apache.logging.log4j:log4j-layout-template-json","purl":"pkg:maven/org.apache.logging.log4j/log4j-layout-template-json","ranges":[">=2.14.0 <2.25.4"],"fixed":["2.25.4"]},{"ecosystem":"Maven","name":"org.apache.logging.log4j:log4j-layout-template-json","purl":"pkg:maven/org.apache.logging.log4j/log4j-layout-template-json","ranges":[">=3.0.0-alpha1 <=3.0.0-beta3"],"fixed":[]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}