CVE-2026-103634: CWE-787 Out-of-bounds write in Apache Software Foundation Apache DataSketches
Description
Out-of-bounds read and write in the Count-Min sketch deserialization of Apache DataSketches C++ (repo: datasketches-cpp). count_min_sketch::deserialize() did not include the preamble in its input size check, so a truncated sketch could cause a read of up to 16 bytes past the end of the input. In addition, the table size was computed from the serialized number of buckets and number of hash functions in 32-bit arithmetic. A crafted sketch could make it wrap to zero, so that the sketch deserialized with an empty table, and later updates and estimate queries read and wrote outside the heap allocation. This can corrupt heap memory, causing a crash and potentially enabling further exploitation. This issue affects Apache DataSketches C++: from 4.1.0 before 5.3.0. Only applications that deserialize Count-Min sketches from untrusted sources are affected. Users are recommended to upgrade to version 5.3.0, which fixes this issue.
Affected software
Apache Software Foundation
Apache DataSketches
pkg:github/apache/datasketches-cppRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-103634 describes a vulnerability in Apache DataSketches C++ Count-Min sketch deserialization where the function count_min_sketch::deserialize() fails to include the preamble in its input size check, allowing reads up to 16 bytes beyond the input buffer if the sketch is truncated. Furthermore, the table size is computed using 32-bit arithmetic from serialized parameters, which can overflow to zero if crafted maliciously. This results in an empty table being deserialized, causing subsequent updates and estimate queries to perform out-of-bounds heap reads and writes. This heap corruption can lead to application crashes and may be exploitable for further attacks. The vulnerability affects versions from 4.1.0 up to and including 5.2.0 and is resolved in version 5.3.0.
Potential Impact
Heap memory corruption caused by out-of-bounds read and write during deserialization of maliciously crafted Count-Min sketches can lead to application crashes and potentially enable further exploitation. The impact is limited to applications that deserialize Count-Min sketches from untrusted sources.
Mitigation Recommendations
Users should upgrade Apache DataSketches C++ to version 5.3.0 or later, where this vulnerability is fixed. Avoid deserializing Count-Min sketches from untrusted or unauthenticated sources until the upgrade is applied.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- apache
- Date Reserved
- 2026-09-30T23:36:49.873Z
- State
- PUBLISHED
Threat ID: 6ad9b4b24d27ba8daa366499
Added to database: 10/22/2026, 07:01:06 UTC
Last enriched: 10/22/2026, 07:16:05 UTC
Last updated: 10/22/2026, 21:15:13 UTC
Views: 10
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