{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-100302", "assignerOrgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09", "state": "PUBLISHED", "assignerShortName": "apache", "dateReserved": "2026-09-25T17:59:47.459Z", "datePublished": "2026-11-04T10:46:20.042Z", "dateUpdated": "2026-11-04T11:09:44.818Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09", "shortName": "apache", "dateUpdated": "2026-11-04T10:46:20.042Z"}, "title": "Apache ZooKeeper: Denial of service through unbounded memory allocation in multiRead request handling", "problemTypes": [{"descriptions": [{"description": "CWE-770 Allocation of resources without limits or throttling", "lang": "en", "cweId": "CWE-770", "type": "CWE"}]}], "source": {"discovery": "UNKNOWN"}, "affected": [{"vendor": "Apache Software Foundation", "product": "Apache ZooKeeper", "packageURL": "pkg:maven/org.apache.zookeeper/zookeeper", "versions": [{"status": "affected", "version": "3.9.0", "lessThanOrEqual": "3.9.6", "versionType": "maven"}, {"status": "affected", "version": "3.8.0", "lessThanOrEqual": "3.8.7", "versionType": "maven"}], "defaultStatus": "unaffected", "collectionURL": "https://repo.maven.apache.org/maven2", "packageName": "org.apache.zookeeper:zookeeper"}], "descriptions": [{"value": "Allocation of Resources Without Limits or Throttling in the multiRead request handler of Apache ZooKeeper allows a remote attacker to crash the server (denial of service) with a single small request.\n\nThe multiRead handler places no limit on the number of bundled read operations or on the cumulative size of the response it builds in memory. Because each operation's result is fully materialized and retained before serialization, a request that is small on the wire \u2014 within the jute.maxbuffer limit \u2014 but that references a large znode many times can force the server to allocate far more heap than the request size implies, exhausting the JVM heap and terminating the server with an OutOfMemoryError. Neither jute.maxbuffer nor largeRequestMaxBytes prevents this, as both bound only the inbound request, not the response.\n\nThis issue affects Apache ZooKeeper from 3.7.0 through 3.9.6. Users are recommended to upgrade to version 3.9.7, which enforces configurable limits on the multiRead operation count and cumulative response size.", "lang": "en", "supportingMedia": [{"type": "text/html", "base64": false, "value": "<p>Allocation of Resources Without Limits or Throttling in the <code>multiRead</code> request handler of Apache ZooKeeper allows a remote attacker to crash the server (denial of service) with a single small request.<br><span><br>The </span><code>multiRead</code><span> handler places no limit on the number of bundled read operations or on the cumulative size of the response it builds in memory. Because each operation's result is fully materialized and retained before serialization, a request that is small on the wire \u2014 within the </span><code>jute.maxbuffer</code><span> limit \u2014 but that references a large znode many times can force the server to allocate far more heap than the request size implies, exhausting the JVM heap and terminating the server with an </span><code>OutOfMemoryError</code><span>. Neither </span><code>jute.maxbuffer</code><span> nor </span><code>largeRequestMaxBytes</code><span> prevents this, as both bound only the inbound request, not the response.<br></span><span><br>This issue affects Apache ZooKeeper from 3.7.0 through 3.9.6. Users are recommended to upgrade to version 3.9.7, which enforces configurable limits on the multiRead operation count and cumulative response size.</span></p>"}]}], "references": [{"url": "https://lists.apache.org/thread.html/gj2vxwx8myq31js6tvb7bgls4nnxohj7", "tags": ["vendor-advisory"]}], "metrics": [{"other": {"type": "Textual description of severity", "content": {"text": "important"}}, "scenarios": [{"lang": "en", "value": "GENERAL"}]}, {"scenarios": [{"lang": "en", "value": "GENERAL"}], "format": "CVSS", "cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "subConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "subIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "version": "4.0", "baseSeverity": "HIGH", "baseScore": 7.1, "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"}}], "x_generator": {"engine": "Vulnogram 1.0.3"}}, "adp": [{"title": "CVE Program Container", "references": [{"url": "http://www.openwall.com/lists/oss-security/2026/11/03/12"}], "providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2026-11-04T11:09:44.818Z"}}]}}

{}

{"affected": [{"affectedData": [{"collectionURL": "https://repo.maven.apache.org/maven2", "defaultStatus": "unaffected", "packageName": "org.apache.zookeeper:zookeeper", "packageURL": "pkg:maven/org.apache.zookeeper/zookeeper", "product": "Apache ZooKeeper", "vendor": "Apache Software Foundation", "versions": [{"lessThanOrEqual": "3.9.6", "status": "affected", "version": "3.9.0", "versionType": "maven"}, {"lessThanOrEqual": "3.8.7", "status": "affected", "version": "3.8.0", "versionType": "maven"}]}], "source": "security@apache.org"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Allocation of Resources Without Limits or Throttling in the multiRead request handler of Apache ZooKeeper allows a remote attacker to crash the server (denial of service) with a single small request.\n\nThe multiRead handler places no limit on the number of bundled read operations or on the cumulative size of the response it builds in memory. Because each operation's result is fully materialized and retained before serialization, a request that is small on the wire \u2014 within the jute.maxbuffer limit \u2014 but that references a large znode many times can force the server to allocate far more heap than the request size implies, exhausting the JVM heap and terminating the server with an OutOfMemoryError. Neither jute.maxbuffer nor largeRequestMaxBytes prevents this, as both bound only the inbound request, not the response.\n\nThis issue affects Apache ZooKeeper from 3.7.0 through 3.9.6. Users are recommended to upgrade to version 3.9.7, which enforces configurable limits on the multiRead operation count and cumulative response size."}], "id": "CVE-2026-100302", "lastModified": "2026-11-04T12:17:05.297", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 7.1, "baseSeverity": "HIGH", "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": "LOW", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/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": "HIGH", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "security@apache.org", "type": "Secondary"}]}, "published": "2026-11-04T11:17:07.023", "references": [{"source": "security@apache.org", "url": "https://lists.apache.org/thread.html/gj2vxwx8myq31js6tvb7bgls4nnxohj7"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "url": "http://www.openwall.com/lists/oss-security/2026/11/03/12"}], "sourceIdentifier": "security@apache.org", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-770"}], "source": "security@apache.org", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[3.9.0,3.9.6]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[3.8.0,3.8.7]"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Apache ZooKeeper", "source": "cna", "vendor": "Apache Software Foundation"}, "product": "zookeeper", "vendor": "apache"}], "created": "2026-11-04T12:30:10.983024+00:00", "updated": "2026-11-04T12:45:13.690392+00:00", "vendors": ["apache", "apache$PRODUCT$zookeeper"]}