CVE-2026-111108

{"id": "CVE-2026-111108", "cveTags": [], "metrics": {}, "affected": [{"source": "security@apache.org", "affectedData": [{"vendor": "Apache Software Foundation", "product": "Apache Kafka", "versions": [{"status": "affected", "version": "3.3.0", "versionType": "semver", "lessThanOrEqual": "4.1.2"}, {"status": "affected", "version": "4.2.0", "versionType": "semver", "lessThanOrEqual": "4.2.1"}, {"status": "affected", "version": "4.3.0", "versionType": "semver", "lessThanOrEqual": "4.3.1"}], "packageURL": "pkg:maven/org.apache.kafka/kafka", "packageName": "org.apache.kafka:kafka", "collectionURL": "https://repo.maven.apache.org/maven2", "defaultStatus": "unaffected"}]}], "published": "2026-10-28T17:17:38.433", "references": [{"url": "https://kafka.apache.org/cve-list", "source": "security@apache.org"}, {"url": "http://www.openwall.com/lists/oss-security/2026/10/28/10", "source": "af854a3a-2127-422b-91ae-364da2661108"}], "vulnStatus": "Awaiting Analysis", "weaknesses": [{"type": "Secondary", "source": "security@apache.org", "description": [{"lang": "en", "value": "CWE-400"}, {"lang": "en", "value": "CWE-770"}, {"lang": "en", "value": "CWE-789"}]}], "descriptions": [{"lang": "en", "value": "Apache Kafka's code-generated protocol readers pre-size an array's collection from the element\u00a0count declared by the sender. That count is checked only against the bytes remaining in the\u00a0request buffer, which assumes about one byte per element; because most elements need several\u00a0bytes, a request can declare far more elements than the buffer holds and still pass. For a\u00a0keyed array the reader then allocates an ImplicitLinkedHashCollection of capacity (2 * count +1), so a request of a few tens of megabytes can force a heap allocation several times larger\u00a0before any element is read. The pattern is emitted into every generated reader, so it affects\u00a0all Kafka API types with an array field.\u00a0\n\n\nImpact:\n\nRequest parsing happens before any authorization check. On a listener that does not require\u00a0authentication (for example PLAINTEXT), an unauthenticated attacker can send a few concurrent\u00a0requests that each declare a very large=\n\narray length and allocate many times their wire size\u00a0in broker heap, crashing the broker with an OutOfMemoryError. The reporter demonstrated three\u00a0concurrent ~90 MB ProduceRequest (v3) connections exhausting a 1 GB heap (~8x amplification).\u00a0On listeners that require authentication, the attacker needs valid credentials but no specific ACL,\u00a0since parsing precedes authorization..\n\n\nMitigation:\n\nUpgrade to Apache Kafka 4.2.2, 4.3.2, or 4.4.0. Until then, lowering socket.request.max.bytes\u00a0and restricting network access to broker listeners reduces, but does not remove, exposure.\n\n\nResolution:\n\nFrom Apache Kafka 4.2.2, 4.3.2, and 4.4.0: generated readers cap the initial array\u00a0pre-allocation at MessageUtil.MAX_PREALLOCATED_ARRAY_CAPACITY (1000) and grow it on demand,\u00a0and reject a declared array length above MessageUtil.MAX_ARRAY_LENGTH (1,000,000)."}], "lastModified": "2026-10-29T15:04:37.187", "sourceIdentifier": "security@apache.org"}