Executive brief
GNU Binutils is a collection of tools used to build and manipulate binary executable files. A malformed ELF object file can trigger a null pointer dereference crash in the linker when processing merged sections with specific options, causing the build process to fail and potentially allowing an attacker to trigger a denial of service.
Technical details
A null pointer dereference vulnerability exists in the _bfd_write_merged_section function (bfd/merge.c:1121) when processing malformed ELF files with merged sections. The vulnerability is triggered when using the linker with `--shared -z now` options on an object file with inconsistent merge state, causing a NULL-derived pointer dereference. The attack is local and requires the attacker to provide a malformed ELF object file to be linked. An attacker can crash the linker or build process. The issue appears to be an incomplete fix for a prior vulnerability (bug 33477) and remains unfixed as of the advisory date.
Affected products
- GNU Binutils 2.47
Timeline
- 2026-07-28: disclosed: Bug reported via Sourceware Bugzilla
- 2026-09-14: advisory: CVE-2026-90830 published