Critical 9.1Published Oct 10, 2026

CVE-2026-103635Apache DataSketches: datasketches-cpp: Out-of-bounds read in compact Theta sketch deserialization allows denial of service via a crafted sketch

Updated under an hour ago (2026-10-19 08:23 UTC)

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It affects Apache Software Foundation Apache DataSketches. Add what you run to find out whether that includes you.

EPSS puts the chance of exploitation in the next 30 days at 0.60%, higher than 48% of scored CVEs.

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Every CVE for Apache Software Foundation Apache DataSketches

Exploited in the last 30 days

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: 9.1 CRITICAL (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Weakness (CWE): CWE-125, CWE-190
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.60% (percentile 48)
Assigned by: apache
NVD analysis: Undergoing Analysis
Record last updated: Oct 16, 2026
First seen by InfoSec Signals: Oct 10, 2026

Affected products

Affected products

Apache Software Foundation Apache DataSketches apache_software_foundation:apache_datasketches (from the name)	from 3.1.0 through 5.2.0	CNA record

References

https://lists.apache.org/thread/15b86y9jstco39kzppjw7l5kvhjvwqvvvendor-advisory
https://github.com/apache/datasketches-cpp/releases/tag/5.3.0release-notes
http://www.openwall.com/lists/oss-security/2026/10/10/5

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.