CVE-2026-103635: out-of-bounds read in compact Theta sketch deserialization in datasketches-cpp

Published on October 10, 2026 in the oss-sec feed by Lee Rhodes, advisory CVE-2026-103635 describes an out-of-bounds read during compact Theta sketch deserialization in Apache DataSketches, in the datasketches-cpp repository. According to the text, deserializing a Theta sketch crafted for this purpose can cause an out-of-bounds read and denial of service. The functions compact_theta_sketch::deserialize() and wrapped_compact_theta_sketch::wrap() read header fields before checking whether the input was large enough. In the compact format, the size check could be bypassed by a 32-bit overflow. The stated severity is low, and the affected versions range from 3.1.0 through 5.2.0. This content is an automatic translation of the feed, and the received text was cut off before the end. To confirm the fixed version, the technical details and the maintainer's recommendations, consult the original advisory on seclists.org, in the oss-sec list for the fourth quarter of 2026, using the identifier CVE-2026-103635 in a search engine or on the list itself. No address or URL of the advisory is reproduced here.