OSV-2025-251 Heap-buffer-overflow in icu_78::RegexMatcher::MatchChunkAt

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=407590995 Crash type: Heap-buffer-overflow READ 2 Crash state: icu78::RegexMatcher::MatchChunkAt icu78::RegexMatcher::findUsingChunk uregexmatchfuzzer.cpp...