# smb: client: fail DACL rewrite when the new DACL exceeds 64K

CVE record · `CVE-2026-97559`

- **Identifiers:** `CVE-2026-97559`
- **State:** Confirmed
- **Severity:** No CVSS score
- **Critical:** No
- **CNA:** Linux
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 25 Sept 2026
- **Updated:** 30 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 25 Sept 2026, 10:21 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: `f5065508897a922327f32223082325d10b069ebc to before f033d6e5aadf3e8c6a12873110557ed40cd71388` (git)
  - affected: `f5065508897a922327f32223082325d10b069ebc to before 284877c6189fda1ac3d81771dd8482660a0c7dc1` (git)
  - affected: `f5065508897a922327f32223082325d10b069ebc to before d433376abc47e10870ae732f89c7c1a60b199a0c` (git)
  - affected: `f5065508897a922327f32223082325d10b069ebc to before 2ef532a01f44687f5b95001e88247cf05bff9892` (git)
  - affected: `f5065508897a922327f32223082325d10b069ebc to before ee13d687d06a6fbb2008625dd560c654231b28e0` (git)
  - affected: `f5065508897a922327f32223082325d10b069ebc to before d05045177a855386bca5e1909e08d06290e6e3b3` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `5.12`
  - unaffected: `before 5.12` (semver)
  - unaffected: `6.1.191 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.160 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.112 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.53 to 6.18.*, inclusive` (semver)
  - unaffected: `7.2.7 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.

> CVE-2026-97559 affects the Linux kernel's SMB client DACL rewrite code (replace_sids_and_copy_aces() and set_chmod_dacl()), which could wrap a 16-bit size accumulator when a rewritten DACL exceeds 64K. The source describes the result as corruption of the DACL sent to the server, and it does not describe what an attacker must do to trigger it. Linux kernel versions from 5.12 up to the fixed commits listed in the record are affected, and the record lists stable fixes in 6.1.191, 6.6.160, 6.12.112 and 6.18.53 and later. Users should update to a fixed kernel version; no workaround is listed.

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

No source has published a CVSS score for this record yet.

- **CISA KEV:** Not listed.
- **EPSS:** 0.0021, the 11th percentile, on 12 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 Sept 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-97559](https://www.cve.org/CVERecord?id=CVE-2026-97559)
- [NVD: CVE-2026-97559](https://nvd.nist.gov/vuln/detail/CVE-2026-97559)

### References from the CNA

- <https://git.kernel.org/stable/c/f033d6e5aadf3e8c6a12873110557ed40cd71388>
- <https://git.kernel.org/stable/c/284877c6189fda1ac3d81771dd8482660a0c7dc1>
- <https://git.kernel.org/stable/c/d433376abc47e10870ae732f89c7c1a60b199a0c>
- <https://git.kernel.org/stable/c/2ef532a01f44687f5b95001e88247cf05bff9892>
- <https://git.kernel.org/stable/c/ee13d687d06a6fbb2008625dd560c654231b28e0>
- <https://git.kernel.org/stable/c/d05045177a855386bca5e1909e08d06290e6e3b3>

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-2026-97559>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-97559/>. Everything for agents: <https://agentprime.io/llms.txt>.