{"id":"CVE-2026-103501","published":"2026-10-10T11:17:34.853","lastModified":"2026-10-16T16:16:53.233","description":"Heap buffer overflow in the HLL sketch deserialization of Apache DataSketches C++ (repo: datasketches-cpp).\n\nWhen deserializing a sketch in LIST mode, from either a byte buffer or a stream, the coupon count was read from the input and used as the number of entries to copy into a fixed buffer of 8 entries, without checking it against the buffer's capacity. A crafted sketch could cause a write of up to 988 bytes past the end of this internal heap buffer. This can corrupt heap memory, causing a crash and potentially enabling further exploitation.\n\nThis issue affects Apache DataSketches C++: from 1.0.0-incubating before 5.3.0. Only applications that deserialize HLL sketches from untrusted sources are affected.\n\nUsers are recommended to upgrade to version 5.3.0, which fixes this issue.","cvssScore":9.8,"cvssSeverity":"CRITICAL","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwes":["CWE-122","CWE-1284"],"vendors":[],"products":[],"references":[{"url":"https://github.com/apache/datasketches-cpp/releases/tag/5.3.0","tags":[]},{"url":"https://lists.apache.org/thread/n2oc2j841dzsv4239jjp08of66bo79c5","tags":[]},{"url":"http://www.openwall.com/lists/oss-security/2026/10/10/2","tags":[]}],"exploitRefs":[{"url":"https://github.com/apache/datasketches-cpp/releases/tag/5.3.0","tags":[]}],"hasPoc":true,"ai":{"summary":"A heap buffer overflow occurs when deserializing HLL sketches in LIST mode from untrusted sources, allowing attackers to write up to 988 bytes past a fixed 8-entry buffer boundary. This can corrupt heap memory and potentially enable further exploitation.","exploitability":"Exploitation is moderately difficult as it requires crafting a malicious sketch file that triggers the deserialization process, but the vulnerability is remotely exploitable since applications deserialize untrusted data from external sources.","blast_radius":"The impact could be significant across systems processing HLL sketches from external sources, potentially affecting analytics pipelines, data processing workflows, and any application using Apache DataSketches C++ for sketch deserialization.","remediation":"Upgrade to version 5.3.0 which fixes this heap buffer overflow vulnerability in the HLL sketch deserialization.","detection":"No reliable host or network indicator is derivable from the published description.","tags":["heap-overflow","deserialization","memory-corruption"],"model":"garnet-coder","analyzedAt":"2026-10-17T08:45:39.145Z"}}