CVE-2026-34480

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Karwasz as pull request #4077"}, {"lang": "en", "time": "2026-03-25T09:46:00.000Z", "value": "Fix verified by reporter"}, {"lang": "en", "time": "2026-03-28T11:19:00.000Z", "value": "Log4j 2.25.4 released"}], "references": [{"url": "https://github.com/apache/logging-log4j2/pull/4077", "tags": ["patch"]}, {"url": "https://logging.apache.org/security.html#CVE-2026-34480", "tags": ["vendor-advisory"]}, {"url": "https://logging.apache.org/cyclonedx/vdr.xml", "tags": ["vendor-advisory"]}, {"url": "https://logging.apache.org/log4j/2.x/manual/layouts.html#XmlLayout", "tags": ["related"]}, {"url": "https://lists.apache.org/thread/5x0hcnng0chhghp6jgjdp3qmbbhfjzhb", "tags": ["vendor-advisory"]}], "x_generator": {"engine": "Vulnogram 0.2.0"}, "descriptions": [{"lang": "en", "value": "Apache Log4j Core's XmlLayout https://logging.apache.org/log4j/2.x/manual/layouts.html#XmlLayout , in versions up to and including 2.25.3, fails to sanitize characters forbidden by the XML 1.0 specification https://www.w3.org/TR/xml/#charsets producing invalid XML output whenever a log message or MDC value contains such characters.\n\nThe impact depends on the StAX implementation in use:\n\n * JRE built-in StAX: Forbidden characters are silently written to the output, producing malformed XML. Conforming parsers must reject such documents with a fatal error, which may cause downstream log-processing systems to drop the affected records.\n * Alternative StAX implementations (e.g., Woodstox https://github.com/FasterXML/woodstox , a transitive dependency of the Jackson XML Dataformat module): An exception is thrown during the logging call, and the log event is never delivered to its intended appender, only to Log4j's internal status logger.\n\n\nUsers are advised to upgrade to Apache Log4j Core 2.25.4, which corrects this issue by sanitizing forbidden characters before XML output.", "supportingMedia": [{"type": "text/html", "value": "<p>Apache Log4j Core's <code><a target=\"_blank\" rel=\"nofollow\" href=\"https://logging.apache.org/log4j/2.x/manual/layouts.html#XmlLayout\">XmlLayout</a></code>, in versions up to and including 2.25.3, fails to sanitize characters forbidden by the <a target=\"_blank\" rel=\"nofollow\" href=\"https://www.w3.org/TR/xml/#charsets\">XML 1.0 specification</a> producing invalid XML output whenever a log message or MDC value contains such characters.</p><p>The impact depends on the StAX implementation in use:</p><ul><li><strong>JRE built-in StAX:</strong> Forbidden characters are silently written to the output, producing malformed XML. 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Los analizadores conformes deben rechazar dichos documentos con un error fatal, lo que puede hacer que los sistemas de procesamiento de registros posteriores descarten los registros afectados.\n * Implementaciones alternativas de StAX (por ejemplo, Woodstox https://github.com/FasterXML/woodstox , una dependencia transitiva del m\u00f3dulo Jackson XML Dataformat): Se lanza una excepci\u00f3n durante la llamada de registro, y el evento de registro nunca se entrega a su appender previsto, solo al registrador de estado interno de Log4j.\n\nSe recomienda a los usuarios actualizar a Apache Log4j Core 2.25.4, que corrige este problema saneando los caracteres prohibidos antes de la salida XML."}], "id": "CVE-2026-34480", "lastModified": "2026-10-26T22:10:00.163", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 6.9, "baseSeverity": "MEDIUM", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "LOW", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "security@apache.org", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-34480", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-04-10T17:43:51.255638Z", "version": "2.0.3"}}]}, "published": "2026-04-10T16:16:31.463", "references": [{"source": "security@apache.org", "tags": ["Issue Tracking", "Patch"], "url": "https://github.com/apache/logging-log4j2/pull/4077"}, {"source": "security@apache.org", "tags": ["Mailing List", "Vendor Advisory"], "url": "https://lists.apache.org/thread/5x0hcnng0chhghp6jgjdp3qmbbhfjzhb"}, {"source": "security@apache.org", "tags": ["Product"], "url": "https://logging.apache.org/cyclonedx/vdr.xml"}, {"source": "security@apache.org", "tags": ["Technical Description"], "url": "https://logging.apache.org/log4j/2.x/manual/layouts.html#XmlLayout"}, {"source": "security@apache.org", "tags": ["Vendor Advisory"], "url": "https://logging.apache.org/security.html#CVE-2026-34480"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Mailing List", "Third Party Advisory"], "url": "http://www.openwall.com/lists/oss-security/2026/04/10/9"}], "sourceIdentifier": "security@apache.org", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-116"}], "source": "security@apache.org", "type": "Secondary"}]}

{"bugzilla": {"description": "org.apache.logging.log4j/log4j-core: Apache Log4j Core: Invalid XML output causes denial of service in logging", "id": "2457328", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2457328"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.3", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L", "status": "draft"}, "cwe": "CWE-168", "details": ["A flaw was found in Apache Log4j Core. The XmlLayout component, responsible for formatting log messages into XML, does not properly remove or replace characters that are not allowed in XML 1.0. When log messages or diagnostic information contain these forbidden characters, the resulting XML output becomes invalid. This can lead to two main issues: either systems processing these logs will fail to read the affected records, or the logging process itself will stop delivering events, both resulting in a denial of service for logging operations."], "mitigation": {"lang": "en:us", "value": "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."}, "name": "CVE-2026-34480", "package_state": [{"cpe": "cpe:/a:redhat:ai_inference_server:3", "fix_state": "Fix deferred", "package_name": "redhat-user-workloads/rhaiis-cuda-ubi9-3-2-2", "product_name": "Red Hat AI Inference Server"}, {"cpe": "cpe:/a:redhat:ai_inference_server:3", "fix_state": "Fix deferred", "package_name": "redhat-user-workloads/rhaiis-cuda-ubi9-3-3", "product_name": "Red Hat AI Inference Server"}, {"cpe": "cpe:/a:redhat:amq_broker:7", "fix_state": "Fix deferred", "package_name": "log4j-core", "product_name": "Red Hat AMQ Broker 7"}, {"cpe": "cpe:/a:redhat:camel_spring_boot:4", "fix_state": "Fix deferred", "package_name": "log4j-core", "product_name": "Red Hat build of Apache Camel for Spring Boot 4"}, {"cpe": "cpe:/a:redhat:apache_camel_hawtio:4", "fix_state": "Fix deferred", "package_name": "log4j-core", "product_name": "Red Hat build of Apache Camel - HawtIO 4"}, {"cpe": "cpe:/a:redhat:service_registry:2", "fix_state": "Fix deferred", "package_name": "log4j-core", "product_name": "Red Hat build of Apicurio Registry 2"}, {"cpe": "cpe:/a:redhat:apicurio_registry:3", "fix_state": "Fix deferred", "package_name": "log4j-core", "product_name": "Red Hat build of Apicurio Registry 3"}, {"cpe": "cpe:/a:redhat:optaplanner:::el6", "fix_state": "Fix deferred", "package_name": "log4j-core", "product_name": "Red Hat build of OptaPlanner 8"}, {"cpe": "cpe:/a:redhat:jboss_data_grid:8", "fix_state": "Fix deferred", "package_name": "log4j-core", "product_name": "Red Hat Data Grid 8"}, {"cpe": "cpe:/a:redhat:jboss_data_grid:8", "fix_state": "Fix deferred", "package_name": "log4j-core-test", "product_name": "Red Hat Data Grid 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "log4j:2/log4j", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "pki-core:10.6/resteasy", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "pki-deps:10.6/resteasy", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "log4j", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "resteasy", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:enterprise_linux_ai:3", "fix_state": "Fix deferred", "package_name": "bazel7", "product_name": "Red Hat Enterprise Linux AI (RHEL AI) 3"}, {"cpe": "cpe:/a:redhat:enterprise_linux_ai:3", "fix_state": "Fix deferred", "package_name": "bazel8", "product_name": "Red Hat Enterprise Linux AI (RHEL AI) 3"}, {"cpe": "cpe:/a:redhat:enterprise_linux_ai:3", "fix_state": "Fix deferred", "package_name": "redhat-user-workloads/bootc-cuda-3-3", "product_name": "Red Hat Enterprise Linux AI (RHEL AI) 3"}, {"cpe": "cpe:/a:redhat:enterprise_linux_ai:3", "fix_state": "Fix deferred", "package_name": "redhat-user-workloads/bootc-cuda-aws-3-3", "product_name": "Red Hat Enterprise Linux AI (RHEL AI) 3"}, {"cpe": "cpe:/a:redhat:enterprise_linux_ai:3", "fix_state": "Fix deferred", "package_name": "redhat-user-workloads/bootc-cuda-azure-3-3", "product_name": "Red Hat Enterprise Linux AI (RHEL AI) 3"}, {"cpe": "cpe:/a:redhat:enterprise_linux_ai:3", "fix_state": "Fix deferred", "package_name": "redhat-user-workloads/bootc-cuda-gcp-3-3", "product_name": "Red Hat Enterprise Linux AI (RHEL AI) 3"}, {"cpe": "cpe:/a:redhat:jboss_fuse:7", "fix_state": "Fix deferred", "package_name": "log4j-core", "product_name": "Red Hat Fuse 7"}, {"cpe": "cpe:/a:redhat:jboss_enterprise_application_platform:7", "fix_state": "Fix deferred", "package_name": "log4j-core", "product_name": "Red Hat JBoss Enterprise Application Platform 7"}, {"cpe": "cpe:/a:redhat:jboss_enterprise_application_platform:8", "fix_state": "Fix deferred", "package_name": "log4j-core", "product_name": "Red Hat JBoss Enterprise Application Platform 8"}, {"cpe": "cpe:/a:redhat:jboss_enterprise_application_platform:8", "fix_state": "Fix deferred", "package_name": "log4j-core-test", "product_name": "Red Hat JBoss Enterprise Application Platform 8"}, {"cpe": "cpe:/a:redhat:jbosseapxp", "fix_state": "Fix deferred", "package_name": "log4j-core", "product_name": "Red Hat JBoss Enterprise Application Platform Expansion Pack"}, {"cpe": "cpe:/a:redhat:jbosseapxp", "fix_state": "Fix deferred", "package_name": "log4j-core-test", "product_name": "Red Hat JBoss Enterprise Application Platform Expansion Pack"}, {"cpe": "cpe:/a:redhat:jboss_enterprise_web_server:6", "fix_state": "Fix deferred", "package_name": "log4j-core", "product_name": "Red Hat JBoss Web Server 6"}, {"cpe": "cpe:/a:redhat:offline_knowledge_portal:1", "fix_state": "Fix deferred", "package_name": "redhat-user-workloads/rhokp-core-encrypted", "product_name": "Red Hat Offline Knowledge Portal"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-modelmesh-rhel8", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-modelmesh-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-pipeline-runtime-datascience-cpu-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-pipeline-runtime-pytorch-cuda-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-pipeline-runtime-pytorch-rocm-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-pipeline-runtime-tensorflow-cuda-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-pipeline-runtime-tensorflow-rocm-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-vllm-cuda-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-vllm-gaudi-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-workbench-jupyter-datascience-cpu-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-workbench-jupyter-pytorch-cuda-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-workbench-jupyter-pytorch-rocm-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-workbench-jupyter-tensorflow-cuda-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-workbench-jupyter-tensorflow-rocm-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Fix deferred", "package_name": "rhoai/odh-workbench-jupyter-trustyai-cpu-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:amq_streams:2", "fix_state": "Fix deferred", "package_name": "log4j-core", "product_name": "streams for Apache Kafka 2"}, {"cpe": "cpe:/a:redhat:amq_streams:3", "fix_state": "Fix deferred", "package_name": "log4j-core", "product_name": "streams for Apache Kafka 3"}], "public_date": "2026-04-10T15:42:03Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-34480\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-34480\nhttps://github.com/apache/logging-log4j2/pull/4077\nhttps://lists.apache.org/thread/5x0hcnng0chhghp6jgjdp3qmbbhfjzhb\nhttps://logging.apache.org/cyclonedx/vdr.xml\nhttps://logging.apache.org/log4j/2.x/manual/layouts.html#XmlLayout\nhttps://logging.apache.org/security.html#CVE-2026-34480"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[2.0-alpha1,2.25.4)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[3.0.0-alpha1,3.0.0-beta3]"}}], "enrichment": {"confidence": 83.0, "confidence_source": "matching", "scores": [{"score": 95.0, "source": "inferred"}, {"score": 83.0, "source": "matching"}]}, "original": {"product": "Apache Log4j Core", "source": "cna", "vendor": "Apache Software Foundation"}, "product": "log4j", "vendor": "apache"}], "analysis": {"en": {"generated_at": "2026-04-14T01:40:42.085738+00:00", "value": {"mitigation_remediation": ["Upgrade Apache Log4j Core to version 2.25.4, which sanitizes forbidden XML characters before output.", "If an immediate upgrade is not possible, remove or replace XmlLayout with a safer layout such as PatternLayout or JSONLayout and reconfigure the logging architecture accordingly.", "Ensure that any auxiliary StAX libraries (e.g., Woodstox) are either removed or mitigated by disabling XmlLayout when they are in use."], "summary": {"action": "Upgrade", "impact": "Log corruption and potential loss of log event data"}, "threat_synthesis": {"affected_systems": "The vulnerability affects Apache Log4j Core versions up to and including 2.25.3, regardless of the underlying StAX implementation. The built\u2011in JRE StAX results in silent corruption, while alternative StAX libraries such as Woodstox cause an exception that prevents the event from reaching its intended appender.", "description_and_impact": "Apache Log4j Core's XmlLayout does not sanitize characters forbidden by the XML 1.0 specification. When log messages or MDC values contain these characters, the layout writes them unchanged or throws an exception, producing malformed XML. Conforming XML parsers then reject the document or downstream systems drop the affected log records, resulting in partial or total loss of log events and loss of audit trail evidence.", "risk_and_exploitability": "The CVSS score is 6.9, indicating a moderate impact. EPSS is below 1\u202f%, and the vulnerability is not listed in the CISA KEV catalog, suggesting a low likelihood of exploitation. Attackers would need to supply log inputs containing forbiddable XML characters; the effect is loss of logging integrity rather than remote code execution. The risk is primarily to incident response and compliance audits where log completeness is essential."}}}}, "created": "2026-04-13T12:44:42.067224+00:00", "updated": "2026-04-14T16:36:24.661356+00:00", "vendors": ["apache", "apache$PRODUCT$log4j"]}