CVE & CISA-KEV Catalog

CVE-2026-103634

UNSCORED

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.

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

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CVSS v3.1 Vector

No CVSS vector data available.

Exploit Intelligence

0.20%probability of exploitation in 30 days
9thpercentile

Low risk: more likely to be exploited than 9% of all known CVEs.

References

Related Vulnerabilities

Other CWE-190 (Integer Overflow) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2020-16040Medium6.5100%-Fix
CVE-2019-11477High7.599%-Fix
CVE-2023-44443High7.894%-Fix
CVE-2014-0569High9.391%--
CVE-2017-3599High7.590%-Fix
CVE-2023-21716Critical9.885%-Fix

Common questions

How do I fix CVE-2026-103634?

No published fix for CVE-2026-103634 has been found yet. Check the linked vendor advisories for guidance as it becomes available.

Is CVE-2026-103634 being actively exploited?

Not that we know of. CVE-2026-103634 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.20% is the estimated probability that it will be exploited in the next 30 days. That is higher than 9% of all scored CVEs.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-10-22.