Created attachment 17852 [details] the relevant fuzz test case From OSS-Fuzz: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=57591 Detailed Report: https://oss-fuzz.com/testcase?key=6174047888343040 ==7133==The signal is caused by a READ memory access. ==7133==Hint: address points to the zero page. SCARINESS: 10 (null-deref) #0 0x559d03a753c2 in ndr_push_CLAIMS_SET_CTR samba/bin/default/librpc/gen_ndr/ndr_claims.c:783:3 #1 0x559d03a753c2 in ndr_push_CLAIMS_SET_NDR samba/bin/default/librpc/gen_ndr/ndr_claims.c:976:4 #2 0x559d03acea20 in ndr_push_struct_blob samba/librpc/ndr/ndr.c:1435:2 #3 0x559d03a7ea68 in ndr_claims_compressed_size samba/librpc/ndr/ndr_claims.c:47:12 #4 0x559d03a76fad in ndr_push_CLAIMS_SET_METADATA samba/bin/default/librpc/gen_ndr/ndr_claims.c:1078:3 #5 0x559d03a15c51 in LLVMFuzzerTestOneInput samba/bin/default/lib/fuzzing/fuzz_ndr_claims_TYPE_STRUCT.c:305:13 #6 0x559d03afd3cb in main #7 0x7fbb0c7f2082 in __libc_start_main /build/glibc-SzIz7B/glibc-2.31/csu/libc-start.c:308:16 #8 0x559d03940afd in _start
This is not a security issue because this code is not yet used outside of tests, besides being only in master and no release branches.
This bug was referenced in samba master: f1174c6e0c4c033b3eae0b9ab94d76ac1382f74b