Описание
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.
A flaw was found in Apache Log4j API. This vulnerability occurs due to improper encoding of non-finite floating-point values during JSON serialization of MapMessages, leading to invalid JSON output. An attacker who can supply a non-finite value can exploit this to cause the affected logging layout to emit malformed JSON. This can corrupt log records or disrupt downstream log ingestion and parsing, potentially leading to a Denial of Service (DoS) or information integrity issues.
Отчет
Important: Apache Log4j API in Red Hat products is affected by improper encoding of non-finite floating-point values during MapMessage JSON serialization. This flaw can lead to malformed JSON output when applications utilize JsonTemplateLayout or similar JSON serialization methods and process attacker-controlled floating-point values. The resulting invalid JSON may disrupt downstream log processing or corrupt log records, requiring specific application configurations for exploitation.
Меры по смягчению последствий
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Cryostat 4 | log4j-api | Fix deferred | ||
| OpenShift Serverless | openshift-serverless-1/kn-eventing-integrations-aws-ddb-streams-source-rhel9 | Fix deferred | ||
| OpenShift Serverless | openshift-serverless-1/kn-eventing-integrations-aws-s3-sink-rhel9 | Fix deferred | ||
| OpenShift Serverless | openshift-serverless-1/kn-eventing-integrations-aws-s3-source-rhel9 | Fix deferred | ||
| OpenShift Serverless | openshift-serverless-1/kn-eventing-integrations-aws-sns-sink-rhel9 | Fix deferred | ||
| OpenShift Serverless | openshift-serverless-1/kn-eventing-integrations-aws-sqs-sink-rhel9 | Fix deferred | ||
| OpenShift Serverless | openshift-serverless-1/kn-eventing-integrations-aws-sqs-source-rhel9 | Fix deferred | ||
| Red Hat AI Inference Server | rhaiis/vllm-cuda-rhel9 | Fix deferred | ||
| Red Hat AI Inference Server | rhaii/vllm-gaudi-rhel9 | Fix deferred | ||
| Red Hat AMQ Broker 7 | log4j-api | Fix deferred |
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Дополнительная информация
Статус:
EPSS
5.9 Medium
CVSS3
Связанные уязвимости
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...
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 attac
Improper encoding of non-finite floating-point values during MapMessag ...
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 at...
EPSS
5.9 Medium
CVSS3