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

CVE record · `CVE-2026-90347`

- **Identifiers:** `CVE-2026-90347`
- **State:** Confirmed
- **Severity:** CVSS 8.4 High
- **Critical:** No
- **CNA:** Linux
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 17 Sept 2026
- **Updated:** 30 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 17 Sept 2026, 16:08 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

## Affected products, as the CNA wrote them

- Vendor: Linux. Product: Linux.
  - affected: `a5cd110cb8369d6b37ef5ccfe56b3fa1338c9615 to before a9e7743b1067ea38c4ad2665d40c3c4a920ad9a9` (git)
  - affected: `a5cd110cb8369d6b37ef5ccfe56b3fa1338c9615 to before 332c9c1a148d0425326989c1187face8f6b2a60c` (git)
  - affected: `a5cd110cb8369d6b37ef5ccfe56b3fa1338c9615 to before ce17c651a90e242ad48df0df89b1e4cebcda5e14` (git)
  - affected: `a5cd110cb8369d6b37ef5ccfe56b3fa1338c9615 to before e9e2854fcff5733ffc607e8ecc87e0e591ab41fd` (git)
  - affected: `a5cd110cb8369d6b37ef5ccfe56b3fa1338c9615 to before f433869f23841a50455c4087d85540d5b4d37cde` (git)
  - affected: `a5cd110cb8369d6b37ef5ccfe56b3fa1338c9615 to before 88b839ce497ccb1ff92f7ae742c78dd2937ba572` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `4.8`
  - unaffected: `before 4.8` (semver)
  - unaffected: `6.1.191 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.160 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.114 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.57 to 6.18.*, inclusive` (semver)
  - unaffected: `7.2.6 to 7.2.*, inclusive` (semver)
  - unaffected: `7.3 to *, inclusive` (original_commit_for_fix)
  - Other versions: affected

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> The Linux kernel's arm64 ptrace code can leave the saved 'orig_x0' value out of sync with x0 during syscall entry, so a tracer's change to the first syscall argument is not seen by seccomp filtering. The source gives few details about the exact impact or who can trigger it. The affected range runs from commit a5cd110cb836 up to several fixed commits, and the fix is listed for 4.8 and later stable branches, including 6.1.191, 6.6.160, 6.12.114 and 6.18.57. Upgrade to a fixed stable kernel release for your branch.

Written 12 Nov 2026.

## Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

## Severity and exploitation

- 8.4 High, CVSS 3.1: `CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N`, from CNA (Linux)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0016, the 5th percentile, on 13 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the CVE Program, published 17 Sept 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-90347](https://www.cve.org/CVERecord?id=CVE-2026-90347)
- [NVD: CVE-2026-90347](https://nvd.nist.gov/vuln/detail/CVE-2026-90347)

### References from the CNA

- <https://git.kernel.org/stable/c/a9e7743b1067ea38c4ad2665d40c3c4a920ad9a9>
- <https://git.kernel.org/stable/c/332c9c1a148d0425326989c1187face8f6b2a60c>
- <https://git.kernel.org/stable/c/ce17c651a90e242ad48df0df89b1e4cebcda5e14>
- <https://git.kernel.org/stable/c/e9e2854fcff5733ffc607e8ecc87e0e591ab41fd>
- <https://git.kernel.org/stable/c/f433869f23841a50455c4087d85540d5b4d37cde>
- <https://git.kernel.org/stable/c/88b839ce497ccb1ff92f7ae742c78dd2937ba572>

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.

## Check whether this affects you

This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it. Compare the affected versions above with what you run.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), `get_advisory` returns this record and `search_advisories` finds related ones. Setup: <https://agentprime.io/mcp.md>
- As JSON: <https://api.agentprime.io/v1/advisories/CVE-2026-90347>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

---

The web page: <https://agentprime.io/advisories/CVE-2026-90347/>. Everything for agents: <https://agentprime.io/llms.txt>.