CVE-2026-103635: critical vulnerability in Apache DataSketches
Apache DataSketches: datasketches-cpp: Out-of-bounds read in compact Theta sketch deserialization allows denial of service via a crafted sketch
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28Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 9.1epss 0.4%
Out-of-bounds read in the compact Theta sketch deserialization of Apache DataSketches C++ (repo: datasketches-cpp).
compact_theta_sketch::deserialize() and wrapped_compact_theta_sketch::wrap() read header fields before checking that the input was long enough. For the compressed format, the size check could be defeated by a 32-bit overflow, and two header fields that control decoding were not validated; this also affected deserialization from a stream. A crafted or truncated sketch could cause a read past the end of the input. In the compressed case the over-read can be large, and the bytes read can become part of the deserialized sketch. This can cause a crash (denial of service) and could expose adjacent memory contents.
This issue affects Apache DataSketches C++: from 3.1.0 before 5.3.0. Only applications that deserialize Theta sketches from untrusted sources are affected.
Users are recommended to upgrade to version 5.3.0, which fixes this issue.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Affected products
Apache Software Foundation · Apache DataSketchesRelated CVEs — Apache DataSketches
In the same product, most dangerous first.
CVE-2026-103501CRITICALApache DataSketches: datasketches-cpp: HLL CouponList Deserialization Buffer Overflow allows memory corruption via a crafted sketchEPSS 0.6%CVE-2026-103634MEDIUMApache DataSketches: datasketches-cpp: Out-of-bounds read and write in Count-Min sketch deserialization allows memory corruption via a crafted sketchEPSS 0.5%CVE-2026-103513CRITICALApache DataSketches: datasketches-cpp: Out-of-bounds read and write in the CPC sketch deserialization allows memory corruption via a crafted sketchEPSS 0.4%CVE-2026-103636HIGHApache DataSketches: datasketches-cpp: Out-of-bounds read in VarOpt union deserialization allows denial of service via a truncated sketchEPSS 0.4%