Created attachment 14078 [details]
Reproducers.

Build Information:
Wireshark git master.
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The following SIGSEGV crash due to an invalid memory write can be observed in an ASAN build of Wireshark (current git master), by feeding a malformed file to tshark ("$ ./tshark -nVxr /path/to/file"):

Attached are two files which trigger the crash.

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==31799==ERROR: AddressSanitizer: SEGV on unknown address 0x00000000fff3 (pc 0x7f538efe2e98 bp 0x7ffff1414290 sp 0x7ffff1413a18 T0)
    #0 0x7f538efe2e97  /build/buildd/eglibc-2.19/string/../sysdeps/x86_64/multiarch/memcpy-ssse3-back.S:1812
    #1 0x4aaeac in __asan_memcpy llvm/projects/compiler-rt/lib/asan/asan_interceptors.cc:393
    #2 0x7f53989ebdee in get_value wireshark/epan/dissectors/packet-btatt.c:6021:9
    #3 0x7f53989cd2a1 in dissect_btatt wireshark/epan/dissectors/packet-btatt.c:6434:40
    #4 0x7f539841bcc1 in call_dissector_through_handle wireshark/epan/packet.c:616:8
    #5 0x7f539840e5ea in call_dissector_work wireshark/epan/packet.c:691:9
    #6 0x7f539840ddbd in dissector_try_uint_new wireshark/epan/packet.c:1148:9
    #7 0x7f5398abde89 in dissect_btl2cap wireshark/epan/dissectors/packet-btl2cap.c:2217:26
    #8 0x7f539841bcc1 in call_dissector_through_handle wireshark/epan/packet.c:616:8
    #9 0x7f539840e5ea in call_dissector_work wireshark/epan/packet.c:691:9
    #10 0x7f53984182be in call_dissector_only wireshark/epan/packet.c:2662:8
    #11 0x7f5398409ccf in call_dissector_with_data wireshark/epan/packet.c:2675:8
    #12 0x7f5398add99f in dissect_btle wireshark/epan/dissectors/packet-btle.c:760:21
    #13 0x7f539841bcc1 in call_dissector_through_handle wireshark/epan/packet.c:616:8
    #14 0x7f539840e5ea in call_dissector_work wireshark/epan/packet.c:691:9
    #15 0x7f53984182be in call_dissector_only wireshark/epan/packet.c:2662:8
    #16 0x7f5398409ccf in call_dissector_with_data wireshark/epan/packet.c:2675:8
    #17 0x7f5398ae089b in dissect_btle_rf wireshark/epan/dissectors/packet-btle_rf.c:221:27
    #18 0x7f539841bcc1 in call_dissector_through_handle wireshark/epan/packet.c:616:8
    #19 0x7f539840e5ea in call_dissector_work wireshark/epan/packet.c:691:9
    #20 0x7f539840ddbd in dissector_try_uint_new wireshark/epan/packet.c:1148:9
    #21 0x7f53989467c5 in dissect_bluetooth wireshark/epan/dissectors/packet-bluetooth.c:1748:10
    #22 0x7f539841bcc1 in call_dissector_through_handle wireshark/epan/packet.c:616:8
    #23 0x7f539840e5ea in call_dissector_work wireshark/epan/packet.c:691:9
    #24 0x7f539840ddbd in dissector_try_uint_new wireshark/epan/packet.c:1148:9
    #25 0x7f539911d5f6 in dissect_frame wireshark/epan/dissectors/packet-frame.c:500:11
    #26 0x7f539841bcc1 in call_dissector_through_handle wireshark/epan/packet.c:616:8
    #27 0x7f539840e5ea in call_dissector_work wireshark/epan/packet.c:691:9
    #28 0x7f53984182be in call_dissector_only wireshark/epan/packet.c:2662:8
    #29 0x7f5398409ccf in call_dissector_with_data wireshark/epan/packet.c:2675:8
    #30 0x7f539840933b in dissect_record wireshark/epan/packet.c:501:3
    #31 0x7f53983b73c9 in epan_dissect_run_with_taps wireshark/epan/epan.c:373:2
    #32 0x5264eb in process_packet wireshark/tshark.c:3728:5
    #33 0x51f960 in load_cap_file wireshark/tshark.c:3484:11
    #34 0x515daf in main wireshark/tshark.c:2197:13

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /build/buildd/eglibc-2.19/string/../sysdeps/x86_64/multiarch/memcpy-ssse3-back.S:1812 
==31799==ABORTING
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This bug is subject to a 90 day disclosure deadline. If 90 days elapse without a broadly available patch, then the bug report will automatically become visible to the public.