This is extracted from a oss-fuzz crash on the GDAL project ( https://oss-fuzz.com/v2/testcase-detail/6214536202813440 : probably not public ), which uses curl master.
It reports a , unfortunately non-reproducible, crash in curl (but this occurs from time to time still). I cannot exclude that GDAL would be the cause, but perhaps you'll see if something is wrong in curl with the following trace:

ERROR: Ran out of file reading SECTUndefinedBehaviorSanitizer:DEADLYSIGNAL
  | ==4==ERROR: UndefinedBehaviorSanitizer: SEGV on unknown address 0x000000000390 (pc 0x7fb367b22855 bp 0x7ffd79e72be0 sp 0x7ffd79e72bc8 T4)
  | ==4==The signal is caused by a READ memory access.
  | ==4==Hint: address points to the zero page.
  | #0 0x7fb367b22854 in pthread_detach
  | #1 0x288c2f5 in Curl_thread_destroy gdal/curl/lib/curl_threads.c:86:5

  | #2 0x283658c in destroy_async_data gdal/curl/lib/asyn-thread.c:363:7

  | #3 0x282b908 in multi_done gdal/curl/lib/multi.c:554:3
  | #4 0x282b384 in curl_multi_remove_handle gdal/curl/lib/multi.c:692:13