# 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.

- **Severity:** High 8.4 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N`)
- **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:** Yes
- **Published:** 17 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-101849, BELL-CVE-2026-90347, DEBIAN-CVE-2026-90347, GHSA-rg84-frxc-rfcx, UBUNTU-CVE-2026-90347

## 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.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90347 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-90347 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-90347/ (Markdown: https://insights.sbomify.com/CVE-2026-90347/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90347
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90347
- OSV: https://osv.dev/vulnerability/CVE-2026-90347

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90347/
Summaries are generated and may contain mistakes; the official description above is the record.