CVE-2026-90347 arm64: ptrace: Keep 'orig_x0' in-sync with x0 on syscall entry
A local attacker can bypass seccomp and audit checks by manipulating syscall arguments via ptrace, requiring a kernel patch.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-90347?
CVE-2026-90347 is a high-severity vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
arm64: ptrace: Keep 'orig_x0' in-sync with x0 on syscall entry
Commit e057b9477232 ("arm64: syscall: Ensure saved x0 is kept in-sync with tracer updates") attempted to resolve a long-standing issue with syscall entry tracing, where a tracer is able to manipulate the first syscall argument without being subjected to seccomp or audit checking.
Unfortunately, that fix was incomplete [1], as it failed to update 'orig_x0' between a tracer updating x0 during a seccomp ptrace exit (SECCOMP_RET_TRACE) and the seccomp filter being re-evaluated.
Rather than add hooks to the core seccomp code, instead move the synchronisation code into the ptrace GPR and syscall setting code so that 'orig_x0' is kept up to date with x0 whenever we're stopped on the syscall entry path.
Which versions are affected by CVE-2026-90347?
How do I fix CVE-2026-90347?
Apply the vendor's patch.
Is CVE-2026-90347 being exploited?
There is no known exploitation of CVE-2026-90347 in the wild and no public exploit code.
Sources
Also known as AZL-101849, BELL-CVE-2026-90347, DEBIAN-CVE-2026-90347, GHSA-rg84-frxc-rfcx, UBUNTU-CVE-2026-90347.