{"id":"CVE-2026-114349","state":"PUBLISHED","title":"Apache Kafka: Denial of service via unbounded memory allocation when decoding compressed record batches","description":"When a broker decodes a compressed record batch, the per-record decoder reads a declared body size from the decompressed stream and allocates a buffer of that size before validating it against the bytes available or any configured limit. The size is attacker-controlled, and the batch CRC does not constrain it, so a small (around 90-byte), CRC-valid compressed produce request can declare a body size of up to about 2 GiB and force the broker to attempt that allocation, raising OutOfMemoryError. The record size limit (max.message.bytes), the request size limit, and client/broker quotas bound only the compressed wire size, not the declared decompressed size.\n\n\nImpact:\n\nAn authenticated principal with Write on a topic can crash broker request-handler threads (reached when a batch's codec differs from the topic's compression.type and records are re-encoded) and any consumer that fetches the record, denying service. On brokers started with -XX:+ExitOnOutOfMemoryError, a common hardening, a single crafted request terminates the broker JVM. More seriously, a crafted record  is accepted at ingest and written to disk; when the log-cleaner later reads it on a compacted topic, the OutOfMemoryError (an Error, not an Exception) terminates the cleaner thread, which is not restarted. With the default of a single cleaner thread, log compaction then stops for the entire broker, including the internal __consumer_offsets and __transaction_state topics, and the condition persists across restarts until the offending record is removed. The impact is availability only; no data is disclosed or altered.\n\n\nMitigation:\n\nUpgrade to Apache Kafka 4.2.2, 4.3.2, or 4.4.0, and set max.decompressed.message.bytes (at the broker and/or topic level) to a bounded value appropriate for your workload. Upgrading alone is not sufficient: for backward compatibility this configuration defaults to an effectively unlimited value (about 2 GiB), so a broker remains exposed until the limit is set. Choose a value at or slightly above the largest legitimate decompressed record your applications produce, and comfortably below the broker heap divided by the number of request-handler and cleaner threads. Until you can upgrade and configure the limit, restrict Write access to trusted producers; quotas and max.message.bytes do not mitigate this issue.\n\n\nResolution:\n\nFrom Apache Kafka 4.2.2, 4.3.2, and 4.4.0: the broker validates a record's declared decompressed body size against max.decompressed.message.bytes before allocating, on the produce-validation, log-compaction, and timestamp-lookup paths, and rejects oversized or negative sizes with InvalidRecordException. Operators must set this configuration to a bounded value to be protected, as its default is effectively unlimited.","publishedAt":"2026-10-28T16:46:54.920Z","updatedAt":"2026-10-29T13:48:26.738Z","severity":null,"assigner":"apache","products":["Apache Software Foundation Apache Kafka"],"affected":[{"vendor":"Apache Software Foundation","product":"Apache Kafka","packageName":"org.apache.kafka:kafka_2.11","packageURL":"pkg:maven/org.apache.kafka/kafka_2.11","defaultStatus":"unaffected","versions":[{"version":"0.11.0.0","status":"affected","lessThan":"2.5.0","versionType":"maven"}],"collectionURL":"https://repo.maven.apache.org/maven2"},{"vendor":"Apache Software Foundation","product":"Apache Kafka","packageName":"org.apache.kafka:kafka_2.12","packageURL":"pkg:maven/org.apache.kafka/kafka_2.12","defaultStatus":"unaffected","versions":[{"version":"0.11.0.0","status":"affected","lessThan":"4.0.0","versionType":"maven"}],"collectionURL":"https://repo.maven.apache.org/maven2"},{"vendor":"Apache Software Foundation","product":"Apache Kafka","packageName":"org.apache.kafka:kafka_2.13","packageURL":"pkg:maven/org.apache.kafka/kafka_2.13","defaultStatus":"unaffected","versions":[{"version":"2.4.0","status":"affected","lessThanOrEqual":"4.1.2","versionType":"maven"},{"version":"4.2.0","status":"affected","lessThanOrEqual":"4.2.1","versionType":"maven"},{"version":"4.3.0","status":"affected","lessThanOrEqual":"4.3.1","versionType":"maven"}],"collectionURL":"https://repo.maven.apache.org/maven2"}],"references":["https://kafka.apache.org/cve-list","https://lists.apache.org/thread/hdy56hrd1h9btf30jb1noswsx32l17dq","http://www.openwall.com/lists/oss-security/2026/10/28/18"],"weaknesses":["CWE-789","CWE-400","CWE-1284"],"ingestedAt":"2026-10-29T20:10:43.281Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/114xxx/CVE-2026-114349.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-114349","state":"PUBLISHED","datePublished":"2026-10-28T16:46:54.920Z","dateUpdated":"2026-10-29T13:48:26.738Z","assignerShortName":"apache","assignerOrgId":"f0158376-9dc2-43b6-827c-5f631a4d8d09","dateReserved":"2026-10-21T08:14:55.090Z"},"containers":{"cna":{"title":"Apache Kafka: Denial of service via unbounded memory allocation when decoding compressed record batches","descriptions":[{"lang":"en","value":"When a broker decodes a compressed record batch, the per-record decoder reads a declared body size from the decompressed stream and allocates a buffer of that size before validating it against the bytes available or any configured limit. The size is attacker-controlled, and the batch CRC does not constrain it, so a small (around 90-byte), CRC-valid compressed produce request can declare a body size of up to about 2 GiB and force the broker to attempt that allocation, raising OutOfMemoryError. The record size limit (max.message.bytes), the request size limit, and client/broker quotas bound only the compressed wire size, not the declared decompressed size.\n\n\nImpact:\n\nAn authenticated principal with Write on a topic can crash broker request-handler threads (reached when a batch's codec differs from the topic's compression.type and records are re-encoded) and any consumer that fetches the record, denying service. On brokers started with -XX:+ExitOnOutOfMemoryError, a common hardening, a single crafted request terminates the broker JVM. More seriously, a crafted record  is accepted at ingest and written to disk; when the log-cleaner later reads it on a compacted topic, the OutOfMemoryError (an Error, not an Exception) terminates the cleaner thread, which is not restarted. With the default of a single cleaner thread, log compaction then stops for the entire broker, including the internal __consumer_offsets and __transaction_state topics, and the condition persists across restarts until the offending record is removed. The impact is availability only; no data is disclosed or altered.\n\n\nMitigation:\n\nUpgrade to Apache Kafka 4.2.2, 4.3.2, or 4.4.0, and set max.decompressed.message.bytes (at the broker and/or topic level) to a bounded value appropriate for your workload. Upgrading alone is not sufficient: for backward compatibility this configuration defaults to an effectively unlimited value (about 2 GiB), so a broker remains exposed until the limit is set. Choose a value at or slightly above the largest legitimate decompressed record your applications produce, and comfortably below the broker heap divided by the number of request-handler and cleaner threads. Until you can upgrade and configure the limit, restrict Write access to trusted producers; quotas and max.message.bytes do not mitigate this issue.\n\n\nResolution:\n\nFrom Apache Kafka 4.2.2, 4.3.2, and 4.4.0: the broker validates a record's declared decompressed body size against max.decompressed.message.bytes before allocating, on the produce-validation, log-compaction, and timestamp-lookup paths, and rejects oversized or negative sizes with InvalidRecordException. Operators must set this configuration to a bounded value to be protected, as its default is effectively unlimited."}],"affected":[{"vendor":"Apache Software Foundation","product":"Apache Kafka","packageName":"org.apache.kafka:kafka_2.11","packageURL":"pkg:maven/org.apache.kafka/kafka_2.11","defaultStatus":"unaffected","versions":[{"version":"0.11.0.0","status":"affected","lessThan":"2.5.0","versionType":"maven"}],"collectionURL":"https://repo.maven.apache.org/maven2"},{"vendor":"Apache Software Foundation","product":"Apache Kafka","packageName":"org.apache.kafka:kafka_2.12","packageURL":"pkg:maven/org.apache.kafka/kafka_2.12","defaultStatus":"unaffected","versions":[{"version":"0.11.0.0","status":"affected","lessThan":"4.0.0","versionType":"maven"}],"collectionURL":"https://repo.maven.apache.org/maven2"},{"vendor":"Apache Software Foundation","product":"Apache Kafka","packageName":"org.apache.kafka:kafka_2.13","packageURL":"pkg:maven/org.apache.kafka/kafka_2.13","defaultStatus":"unaffected","versions":[{"version":"2.4.0","status":"affected","lessThanOrEqual":"4.1.2","versionType":"maven"},{"version":"4.2.0","status":"affected","lessThanOrEqual":"4.2.1","versionType":"maven"},{"version":"4.3.0","status":"affected","lessThanOrEqual":"4.3.1","versionType":"maven"}],"collectionURL":"https://repo.maven.apache.org/maven2"}],"references":[{"url":"https://kafka.apache.org/cve-list","tags":["vendor-advisory"]},{"url":"https://lists.apache.org/thread/hdy56hrd1h9btf30jb1noswsx32l17dq","tags":["mailing-list"]}],"metrics":[{"other":{"type":"Textual description of severity","content":{"text":"important"}},"scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-789","description":"CWE-789 Memory allocation with excessive size value","lang":"en","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-400","description":"CWE-400 Uncontrolled Resource Consumption","lang":"en","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-1284","description":"CWE-1284 Improper validation of specified quantity in input","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"apache","orgId":"f0158376-9dc2-43b6-827c-5f631a4d8d09","dateUpdated":"2026-10-29T13:48:26.738Z"},"source":{"discovery":"EXTERNAL"},"credits":[{"lang":"en","value":"Peyton Kennedy ","type":"reporter"},{"lang":"en","value":"Trung Nguyen , CyStack","type":"reporter"},{"lang":"en","value":"Bartłomiej Dmitruk , Striga","type":"reporter"},{"lang":"en","value":"임성민 ","type":"reporter"},{"lang":"en","value":"Mike Read (GitHub: Michael-JRead)","type":"reporter"},{"lang":"en","value":"Salman Aljardan ","type":"reporter"},{"lang":"en","value":"Yuchao Zhang ","type":"reporter"},{"lang":"en","value":"Yu Bao , PayPal Cyber Security Team","type":"reporter"},{"lang":"en","value":"Vamsi K ","type":"reporter"},{"lang":"en","value":"Srinivas Akhil Mallela ","type":"remediation developer"},{"lang":"en","value":"Ashish Modi, OpenLogic by Perforce","type":"reporter"}],"x_generator":{"engine":"Vulnogram 1.0.3"}},"adp":[{"title":"CVE Program Container","references":[{"url":"http://www.openwall.com/lists/oss-security/2026/10/28/18"}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2026-10-28T20:06:58.727Z"}}]}}}