Heap/stack buffer overflow in the dlang_lname function in d-demangle.c in libiberty allows attackers to potentially cause a denial of service (segmentation fault and crash) via a crafted mangled symbol.
https://github.com/Live-Hack-CVE/CVE-2021-3826
https://gcc.gnu.org/pipermail/gcc-patches/2021-September/579987
https://gcc.gnu.org/git/?p=gcc.git%3Ba=commit%3Bh=5481040197402be6dfee265bd2ff5a4c88e30505
https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-27075
https://cert-portal.siemens.com/productcert/html/ssa-398330.html