# smb/client: fix chown/chgrp with SMB3 POSIX Extensions

CVE record · `CVE-2026-64388`

- **Identifiers:** `CVE-2026-64388`
- **State:** Confirmed
- **Severity:** CVSS 7.8 High
- **Critical:** No
- **CNA:** Linux
- **Weakness (CWE):** [CWE-682](https://cwe.mitre.org/data/definitions/682.html)
- **Tags:** [CWE-682](https://agentprime.io/advisories/tag/cwe-682.md)
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 25 Jul 2026
- **Updated:** 30 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 25 Jul 2026, 08:50 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: `b326614ea2159ea5c835d320f261d05d080cd201 to before c0fe1118a1471d459f76c3e70ff2abbf784ce6bf` (git)
  - affected: `b326614ea2159ea5c835d320f261d05d080cd201 to before 6825a45f6b8ef76b0ee32649ec3d6e39ca143a18` (git)
  - affected: `b326614ea2159ea5c835d320f261d05d080cd201 to before 27ead8c5418af6bfab711079fecb9414d78d4cae` (git)
  - affected: `b326614ea2159ea5c835d320f261d05d080cd201 to before 3eaec47518e126e6dcd1a48521d740278073f0ec` (git)
  - affected: `b326614ea2159ea5c835d320f261d05d080cd201 to before 550cfb8a81181331d4d0f76ab75ee58a0bf41e3e` (git)
  - affected: `b326614ea2159ea5c835d320f261d05d080cd201 to before 760ef2c579c2609cf17fb1cd5392f64d42d43d33` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `4.18`
  - unaffected: `before 4.18` (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: `7.1.4 to 7.1.*, inclusive` (semver)
  - unaffected: `7.2 to *, inclusive` (original_commit_for_fix)
  - Other versions: affected

## 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

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

- **CISA KEV:** Not listed.
- **EPSS:** 0.0013, the 2nd percentile, on 5 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 25 Jul 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-64388](https://www.cve.org/CVERecord?id=CVE-2026-64388)
- [NVD: CVE-2026-64388](https://nvd.nist.gov/vuln/detail/CVE-2026-64388)

### References from the CNA

- <https://git.kernel.org/stable/c/c0fe1118a1471d459f76c3e70ff2abbf784ce6bf>
- <https://git.kernel.org/stable/c/6825a45f6b8ef76b0ee32649ec3d6e39ca143a18>
- <https://git.kernel.org/stable/c/27ead8c5418af6bfab711079fecb9414d78d4cae>
- <https://git.kernel.org/stable/c/3eaec47518e126e6dcd1a48521d740278073f0ec>
- <https://git.kernel.org/stable/c/550cfb8a81181331d4d0f76ab75ee58a0bf41e3e>
- <https://git.kernel.org/stable/c/760ef2c579c2609cf17fb1cd5392f64d42d43d33>

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-2026-64388>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-64388/>. Everything for agents: <https://agentprime.io/llms.txt>.