Detailed report: https://oss-fuzz.com/testcase?key=6241926188630016 Project: libreoffice Fuzzer: libFuzzer_libreoffice_xlsfuzzer Fuzz target binary: xlsfuzzer Job Type: libfuzzer_ubsan_libreoffice Platform Id: linux Crash Type: Bad-cast Crash Address: 0x000018c7b2c0 Crash State: Bad-cast to LogicalFontInstance from invalid vptr GlyphCache::IFSD_Equal::operator std::__1::__hash_iterator, void*>*> std::__1::__hash_table, std::__1::__unordered_map_hasher, GlyphCache::IFSD_Hash, true>, std::__1::__unordered_map_equal, GlyphCache::IFSD_Equal, true>, std::__1::allocator > >::find Sanitizer: undefined (UBSAN) Recommended Security Severity: High Reproducer Testcase: https://oss-fuzz.com/download?testcase_id=6241926188630016 Issue filed automatically. See https://github.com/google/oss-fuzz/blob/master/docs/reproducing.md for more information. Note: This crash might not be reproducible with the provided testcase. That said, for the past 14 days we've been seeing this crash frequently. If you are unable to reproduce this, please try a speculative fix based on the crash stacktrace in the report. The fix can be verified by looking at the crash statistics in the report, a day after the fix is deployed. We will auto-close the bug if the crash is not seen for 14 days. This bug is subject to a 90 day disclosure deadline. If 90 days elapse without an upstream patch, then the bug report will automatically become visible to the public. When you fix this bug, please * mention the fix revision(s). * state whether the bug was a short-lived regression or an old bug in any stable releases. * add any other useful information. This information can help downstream consumers. If you need to contact the OSS-Fuzz team with a question, concern, or any other feedback, please file an issue at https://github.com/google/oss-fuzz/issues.