See also https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=44466 and #20744 (comment)
Steps to reproduce on a fresh install of Ubuntu Focal:
export DEBIAN_FRONTEND=noninteractive && apt update && apt install curl wget htop git vim ccache -y && git clone https://github.com/bitcoin/bitcoin.git bitcoin-core && cd bitcoin-core && apt install build-essential libtool autotools-dev automake pkg-config bsdmainutils python3-zmq make automake cmake curl clang llvm libc++-dev libc++abi-dev g++-multilib libtool binutils-gold bsdmainutils pkg-config python3 patch bison -y && ( cd depends && make DEBUG=1 NO_QT=1 NO_WALLET=1 NO_ZMQ=1 NO_UPNP=1 NO_NATPMP=1 -j $(nproc) ) && ./autogen.sh && CONFIG_SITE="$PWD/depends/x86_64-pc-linux-gnu/share/config.site" ./configure CC='clang ' CXX='clang++ -stdlib=libc++' --enable-fuzz --with-sanitizers=fuzzer && make -j $(nproc)
$ FUZZ=tx_pool ./src/test/fuzz/fuzz
UndefinedBehaviorSanitizer:DEADLYSIGNAL
==52419==ERROR: UndefinedBehaviorSanitizer: SEGV on unknown address 0x000000000008 (pc 0x7f5d814ccb47 bp 0x7fff699e4ef0 sp 0x7fff699e4ea0 T52419)
==52419==The signal is caused by a READ memory access.
==52419==Hint: address points to the zero page.
[#0](/bitcoin-bitcoin/0/) 0x7f5d814ccb47 in std::__1::__libcpp_db::swap(void*, void*) (/lib/x86_64-linux-gnu/libc++.so.1+0x43b47)
[#1](/bitcoin-bitcoin/1/) 0x564aea7e1377 in std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::basic_string(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >&&) (/bitcoin-core/src/test/fuzz/fuzz+0x577377)
[#2](/bitcoin-bitcoin/2/) 0x564aea80cf94 in std::__1::__fs::filesystem::path::path(std::__1::__fs::filesystem::path&&) (/bitcoin-core/src/test/fuzz/fuzz+0x5a2f94)
[#3](/bitcoin-bitcoin/3/) 0x564aea80bd04 in fs::path::path(std::__1::__fs::filesystem::path) (/bitcoin-core/src/test/fuzz/fuzz+0x5a1d04)
[#4](/bitcoin-bitcoin/4/) 0x564aeb1f46ad in fs::absolute(fs::path const&) (/bitcoin-core/src/test/fuzz/fuzz+0xf8a6ad)
[#5](/bitcoin-bitcoin/5/) 0x564aeb1f4c8b in ArgsManager::GetDataDir(bool) const (/bitcoin-core/src/test/fuzz/fuzz+0xf8ac8b)
[#6](/bitcoin-bitcoin/6/) 0x564aea80bbfa in ArgsManager::GetDataDirNet() const (/bitcoin-core/src/test/fuzz/fuzz+0x5a1bfa)
[#7](/bitcoin-bitcoin/7/) 0x564aeb1fa2bb in AbsPathForConfigVal(fs::path const&, bool) (/bitcoin-core/src/test/fuzz/fuzz+0xf902bb)
[#8](/bitcoin-bitcoin/8/) 0x564aeb0d5074 in init::SetLoggingOptions(ArgsManager const&) (/bitcoin-core/src/test/fuzz/fuzz+0xe6b074)
[#9](/bitcoin-bitcoin/9/) 0x564aeaaddd15 in InitLogging(ArgsManager const&) (/bitcoin-core/src/test/fuzz/fuzz+0x873d15)
[#10](/bitcoin-bitcoin/10/) 0x564aeaa06412 in BasicTestingSetup::BasicTestingSetup(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, std::__1::vector<char const*, std::__1::allocator<char const*> > const&) (/bitcoin-core/src/test/fuzz/fuzz+0x79c412)
[#11](/bitcoin-bitcoin/11/) 0x564aeaa073e2 in ChainTestingSetup::ChainTestingSetup(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, std::__1::vector<char const*, std::__1::allocator<char const*> > const&) (/bitcoin-core/src/test/fuzz/fuzz+0x79d3e2)
[#12](/bitcoin-bitcoin/12/) 0x564aeaa0877f in TestingSetup::TestingSetup(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, std::__1::vector<char const*, std::__1::allocator<char const*> > const&) (/bitcoin-core/src/test/fuzz/fuzz+0x79e77f)
[#13](/bitcoin-bitcoin/13/) 0x564aea85508d in std::__1::__unique_if<TestingSetup const>::__unique_single std::__1::make_unique<TestingSetup const, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, std::__1::vector<char const*, std::__1::allocator<char const*> > const&>(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, std::__1::vector<char const*, std::__1::allocator<char const*> > const&) (/bitcoin-core/src/test/fuzz/fuzz+0x5eb08d)
[#14](/bitcoin-bitcoin/14/) 0x564aea852a22 in std::__1::unique_ptr<TestingSetup const, std::__1::default_delete<TestingSetup const> > MakeNoLogFileContext<TestingSetup const>(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, std::__1::vector<char const*, std::__1::allocator<char const*> > const&) (/bitcoin-core/src/test/fuzz/fuzz+0x5e8a22)
[#15](/bitcoin-bitcoin/15/) 0x564aea9c5817 in (anonymous namespace)::initialize_tx_pool() (/bitcoin-core/src/test/fuzz/fuzz+0x75b817)
[#16](/bitcoin-bitcoin/16/) 0x564aea7c8d20 in decltype(std::__1::forward<void (*&)()>(fp)()) std::__1::__invoke<void (*&)()>(void (*&)()) (/bitcoin-core/src/test/fuzz/fuzz+0x55ed20)
[#17](/bitcoin-bitcoin/17/) 0x564aea7c8c6d in void std::__1::__invoke_void_return_wrapper<void>::__call<void (*&)()>(void (*&)()) (/bitcoin-core/src/test/fuzz/fuzz+0x55ec6d)
[#18](/bitcoin-bitcoin/18/) 0x564aea7c8c0d in std::__1::__function::__alloc_func<void (*)(), std::__1::allocator<void (*)()>, void ()>::operator()() (/bitcoin-core/src/test/fuzz/fuzz+0x55ec0d)
[#19](/bitcoin-bitcoin/19/) 0x564aea7c7049 in std::__1::__function::__func<void (*)(), std::__1::allocator<void (*)()>, void ()>::operator()() (/bitcoin-core/src/test/fuzz/fuzz+0x55d049)
[#20](/bitcoin-bitcoin/20/) 0x564aeaab965c in std::__1::__function::__value_func<void ()>::operator()() const (/bitcoin-core/src/test/fuzz/fuzz+0x84f65c)
[#21](/bitcoin-bitcoin/21/) 0x564aeaab95e5 in std::__1::function<void ()>::operator()() const (/bitcoin-core/src/test/fuzz/fuzz+0x84f5e5)
[#22](/bitcoin-bitcoin/22/) 0x564aeb25ac9d in initialize() (/bitcoin-core/src/test/fuzz/fuzz+0xff0c9d)
[#23](/bitcoin-bitcoin/23/) 0x564aeb25b71f in LLVMFuzzerInitialize (/bitcoin-core/src/test/fuzz/fuzz+0xff171f)
[#24](/bitcoin-bitcoin/24/) 0x564aea743437 in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) (/bitcoin-core/src/test/fuzz/fuzz+0x4d9437)
[#25](/bitcoin-bitcoin/25/) 0x564aea76df22 in main (/bitcoin-core/src/test/fuzz/fuzz+0x503f22)
[#26](/bitcoin-bitcoin/26/) 0x7f5d810e60b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)
[#27](/bitcoin-bitcoin/27/) 0x564aea719e7d in _start (/bitcoin-core/src/test/fuzz/fuzz+0x4afe7d)
UndefinedBehaviorSanitizer can not provide additional info.
SUMMARY: UndefinedBehaviorSanitizer: SEGV (/lib/x86_64-linux-gnu/libc++.so.1+0x43b47) in std::__1::__libcpp_db::swap(void*, void*)
==52419==ABORTING