CVE-2026-103501
Heap buffer overflow in the HLL sketch deserialization of Apache DataSketches C++ (repo: datasketches-cpp). When 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. This 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. Users are recommended to upgrade to version 5.3.0, which fixes this issue.
Executive briefing
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Evidence confidence: Not assessed Evidence-derived, not an exploitability verdict
Severity & attack characteristics
CVSS vector:Not supplied
No CVSS vector is currently available in the source record.
Technical explanation & impact
Technical root-cause details are not available in the current source record.
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Affected products and versions
NVD has not supplied machine-readable vulnerable CPE product/version entries for this CVE. This is an information gap, not proof that no products are affected. Check the vendor advisory references below.
Remediation & validation
- Identify exposure by comparing the affected product and version ranges with your asset inventory, SBOM and externally exposed services.
- Review the linked vendor security advisory or patch notes. Upgrade to a vendor-confirmed fixed release; do not infer a fixed version from the CVE description.
- Until patched, consider restricting network access or disabling the affected feature where operationally safe. These are temporary controls, not a substitute for a vendor fix.
- Validate the remediation with a version check and vulnerability rescan, then retain change evidence.
No fixed version is displayed unless it is explicitly established by a vendor advisory. Follow the vendor's release notes for exact product and branch applicability.
Vendor advisories, patches & exploit references
No external references are currently supplied in the CVE record.