arm64: ptrace: Keep 'orig_x0' in-sync with x0 on syscall entry (CVE-2026-90347) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-90347

arm64: ptrace: Keep 'orig_x0' in-sync with x0 on syscall entry

Answer in brief

CVE-2026-90347 records a Unknown severity vulnerability in arm64: ptrace: Keep 'orig_x0' in-sync with x0 on syscall entry. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 17, 2026Updated Sep 17, 2026Source checked Sep 17, 2026First seen by HOL Sep 17, 2026Material review Sep 17, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=a5cd110cb8369d6b37ef5ccfe56b3fa1338c9615 <f433869f23841a50455c4087d85540d5b4d37cde \|\| >=a5cd110cb8369d6b37ef5ccfe56b3fa1338c9615 <88b839ce497ccb1ff92f7ae742c78dd2937ba572	f433869f23841a50455c4087d85540d5b4d37cde, 88b839ce497ccb1ff92f7ae742c78dd2937ba572
Linux/Linuxgeneric	4.8	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to f433869f23841a50455c4087d85540d5b4d37cde if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 17, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 17, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 17, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.