# dm ioctl: don't let data_start run past the buffer

CVE record · `CVE-2026-99063`

- **Identifiers:** `CVE-2026-99063`
- **State:** Confirmed
- **Severity:** No CVSS score
- **Critical:** No
- **CNA:** Linux
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 23 Oct 2026
- **Updated:** 30 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 23 Oct 2026, 12:23 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: `76c072b48e39e9291fbf02d6c912cf27d65e093d to before aaa93e41ae308ad9ff9d9ba3296a0d0f4d45bad3` (git)
  - affected: `76c072b48e39e9291fbf02d6c912cf27d65e093d to before f171054f3c4cfc4dc0cb622ec5b15793e5f23029` (git)
  - affected: `76c072b48e39e9291fbf02d6c912cf27d65e093d to before afe80ec31464f4c54cc1bc658753bc14cb14bd6c` (git)
  - affected: `76c072b48e39e9291fbf02d6c912cf27d65e093d to before 98195e822343a656b92e235847ab3e72b1a3f920` (git)
  - affected: `76c072b48e39e9291fbf02d6c912cf27d65e093d to before e5c3f3d8935ecc64c962fb66e6a86dbf79218f61` (git)
  - affected: `76c072b48e39e9291fbf02d6c912cf27d65e093d to before 5680b6fb3054677d4ee65d3baba24b649f1b430e` (git)
  - affected: `76c072b48e39e9291fbf02d6c912cf27d65e093d to before 725b49c689bbb29ef740b0d6b5ea9390baa9a695` (git)
  - affected: `76c072b48e39e9291fbf02d6c912cf27d65e093d to before 9b3fcf519d370df94a56f3b272d9eddffffa5be8` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `2.6.25`
  - unaffected: `before 2.6.25` (semver)
  - unaffected: `5.10.273 to 5.10.*, inclusive` (semver)
  - unaffected: `5.15.224 to 5.15.*, inclusive` (semver)
  - unaffected: `6.1.191 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.160 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.113 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.57 to 6.18.*, inclusive` (semver)
  - unaffected: `7.2.11 to 7.2.*, inclusive` (semver)
  - unaffected: `7.3 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

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

- **CISA KEV:** Not listed.
- **EPSS:** 0.0018, the 7th percentile, on 6 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 23 Oct 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-99063](https://www.cve.org/CVERecord?id=CVE-2026-99063)
- [NVD: CVE-2026-99063](https://nvd.nist.gov/vuln/detail/CVE-2026-99063)

### References from the CNA

- <https://git.kernel.org/stable/c/aaa93e41ae308ad9ff9d9ba3296a0d0f4d45bad3>
- <https://git.kernel.org/stable/c/f171054f3c4cfc4dc0cb622ec5b15793e5f23029>
- <https://git.kernel.org/stable/c/afe80ec31464f4c54cc1bc658753bc14cb14bd6c>
- <https://git.kernel.org/stable/c/98195e822343a656b92e235847ab3e72b1a3f920>
- <https://git.kernel.org/stable/c/e5c3f3d8935ecc64c962fb66e6a86dbf79218f61>
- <https://git.kernel.org/stable/c/5680b6fb3054677d4ee65d3baba24b649f1b430e>
- <https://git.kernel.org/stable/c/725b49c689bbb29ef740b0d6b5ea9390baa9a695>
- <https://git.kernel.org/stable/c/9b3fcf519d370df94a56f3b272d9eddffffa5be8>

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-2026-99063>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-99063/>. Everything for agents: <https://agentprime.io/llms.txt>.