CVE-2026-103636
UnknownSummary
Out-of-bounds read in the VarOpt union deserialization of Apache DataSketches C++ (datasketches-cpp). var_opt_union::deserialize() read the 32-byte preamble after checking only 8 bytes were available, so a truncated serialized union could cause a read of up to 24 bytes past the end of the input. This can cause a crash (denial of service) and could expose adjacent memory contents. Affects versions from 2.0.0-incubating before 5.3.0.
Risk Assessment
Applications deserializing VarOpt unions from untrusted sources may crash or leak memory contents. This can result in denial of service and data exposure.
Recommendation
Upgrade Apache DataSketches C++ to version 5.3.0. Avoid deserializing VarOpt unions from untrusted sources.
Other vulnerabilities in Apache DataSketches C++
See all- CVE-2026-103635Unknown
Out-of-bounds read in the compact Theta sketch deserialization of Apache DataSketches C++ (datasketches-cpp). compact_theta_sketch::deserialize() and wrapped_compact_theta_sketch::wrap() read header fields before checking input length; in the compressed format the size check could be defeated by a 32-bit overflow. A crafted or truncated sketch could cause a read past the end of the input, potentially large in the compressed case, leading to a crash and memory exposure. Affects versions from 3.1.0 before 5.3.0.
- CVE-2026-103513Unknown
Out-of-bounds read and write in the CPC sketch deserialization of Apache DataSketches C++ (datasketches-cpp). A crafted serialized CPC sketch passed to cpc_sketch::deserialize() can cause the decompressor to read past the end of compressed data, and in the hybrid flavor can cause a write outside an internal heap buffer due to unvalidated decoded row indices. This can corrupt heap memory, causing a crash and potentially enabling further exploitation. Affects versions from 2.0.0-incubating before 5.3.0.
- CVE-2026-103501Unknown
Heap buffer overflow in the HLL sketch deserialization of Apache DataSketches C++ (datasketches-cpp). When deserializing a sketch in LIST mode, the coupon count was read from input and used as the number of entries to copy into a fixed buffer of 8 entries without checking capacity. A crafted sketch could cause a write of up to 988 bytes past the end of the internal heap buffer, corrupting memory. Affects versions from 1.0.0-incubating before 5.3.0.
Original NVD description (English source)
Out-of-bounds read in the VarOpt union deserialization of Apache DataSketches C++ (repo: datasketches-cpp). var_opt_union::deserialize() read the 32-byte preamble of a non-empty union after checking that only 8 bytes were available, so a truncated serialized union could cause a read of up to 24 bytes past the end of the input. For such inputs, the size remaining for the embedded sketch was also computed by an unsigned subtraction that could wrap around, so the embedded sketch's own size checks no longer limited reads to the input. The bytes read can become part of the deserialized union's state. This can cause a crash (denial of service) and could expose adjacent memory contents. This issue affects Apache DataSketches C++: from 2.0.0-incubating before 5.3.0. Only applications that deserialize VarOpt unions from untrusted sources are affected. Users are recommended to upgrade to version 5.3.0, which fixes this issue.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS