[ CVE-2026-49844 · Published 10 Jul 2026 ]
Vulnerability in Apache Software Foundation Apache Log4j API
[ Description ]Official description
Improper encoding of non-finite floating-point values during MapMessage JSON serialization in Apache Log4j API produces output that is not valid JSON. This issue affects Apache Log4j API versions 2.13.1 through 2.25.4 and version 2.26.0. The fix for CVE-2026-34481 did not cover all code paths: when a MapMessage contains a non-finite IEEE 754 value (NaN, Infinity, or -Infinity), MapMessage.asJson() emits the corresponding bare token. RFC 8259 does not permit these tokens, so a conformant parser rejects the resulting document. The defect is reachable only when both of the following conditions hold: * The application uses the message resolver https://logging.apache.org/log4j/2.x/manual/json-template-layout.html#event-template-resolver-message of JsonTemplateLayout or any other layout that relies on MapMessage.asJson() or MapMessage.getFormattedMessage(new String[]{"JSON"}). * The application logs a MapMessage that contains an attacker-controlled floating-point value. An attacker who can supply a non-finite value can cause the affected layout to emit malformed JSON, which may corrupt the enclosing log record or disrupt downstream log ingestion and parsing. Users are advised to upgrade to Apache Log4j API 2.25.5 or 2.26.1, both of which emit RFC 8259-compliant JSON for non-finite values.
[ Fixes ]Fixes and patches
No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.
[ Advisories ]Government CERT advisories
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NCSC-NLNCSC-2026-0448
Vulnerabilities fixed in Oracle Fusion Middleware Translated from Dutch
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CERT-FRCERTFR-2026-AVI-1355
Multiple vulnerabilities in Oracle Weblogic Translated from French
Multiple vulnerabilities have been discovered in Oracle Weblogic. They allow an attacker to cause remote denial of service, a breach of data confidentiality and a breach of data integrity.
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BSI CERT-BundWID-SEC-2026-4092
Oracle Commerce: Multiple vulnerabilities Translated from German
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BSI CERT-BundWID-SEC-2026-4090
Oracle Communications: Multiple vulnerabilities Translated from German
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BSI CERT-BundWID-SEC-2026-4089
Oracle Construction and Engineering: Multiple vulnerabilities Translated from German
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BSI CERT-BundWID-SEC-2026-4086
Oracle Financial Services Applications: Multiple vulnerabilities Translated from German
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BSI CERT-BundWID-SEC-2026-4078
Oracle Fusion Middleware: Multiple vulnerabilities Translated from German
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BSI CERT-BundWID-SEC-2026-4062
Oracle Utilities Applications: Multiple vulnerabilities Translated from German
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CERT-FRCERTFR-2026-AVI-1336
Multiple vulnerabilities in IBM products Translated from French
Multiple vulnerabilities have been discovered in IBM products. Some of them allow an attacker to cause remote arbitrary code execution, privilege escalation and remote denial of service.
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CERT-FRCERTFR-2026-AVI-1291
Multiple vulnerabilities in IBM products Translated from French
Multiple vulnerabilities have been discovered in IBM products. Some of them allow an attacker to cause remote arbitrary code execution, privilege escalation and remote denial of service.
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CERT-FRCERTFR-2026-AVI-1249
Multiple vulnerabilities in VMware products Translated from French
Multiple vulnerabilities have been discovered in VMware products. They allow an attacker to cause a security problem not specified by the vendor.
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CERT-FRCERTFR-2026-AVI-1256
Multiple vulnerabilities in IBM products Translated from French
Multiple vulnerabilities have been discovered in IBM products. Some of them allow an attacker to cause remote arbitrary code execution, privilege escalation and remote denial of service.