# KVM: Replace guest-triggerable BUG_ON() in ioeventfd datamatch with get_unaligned()

CVE record · `CVE-2026-63806`

- **Identifiers:** `CVE-2026-63806`
- **State:** Confirmed
- **Severity:** CVSS 7.1 High
- **Critical:** No
- **CNA:** Linux
- **Weakness (CWE):** [CWE-400](https://cwe.mitre.org/data/definitions/400.html)
- **Tags:** [Denial of service](https://agentprime.io/advisories/tag/dos.md)
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 19 Jul 2026
- **Updated:** 19 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 19 Jul 2026, 12:02 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: `d34e6b175e61821026893ec5298cc8e7558df43a to before 2426c15c1395b7d5ccf1e5025ca898af7f3decb6` (git)
  - affected: `d34e6b175e61821026893ec5298cc8e7558df43a to before 4186c850789906b875a1d263377a4d37c078e317` (git)
  - affected: `d34e6b175e61821026893ec5298cc8e7558df43a to before 36ff44fb3d89960391e013fb9d91e23dbc48be47` (git)
  - affected: `d34e6b175e61821026893ec5298cc8e7558df43a to before 92fc631b69deb1c7d56aec2663003600799dcd75` (git)
  - affected: `d34e6b175e61821026893ec5298cc8e7558df43a to before bf89e3738480d33cd515b4a18900e8443d40cd2e` (git)
  - affected: `d34e6b175e61821026893ec5298cc8e7558df43a to before 5da9b1a87ec7cc3489c27016313524769f12d9e0` (git)
  - affected: `d34e6b175e61821026893ec5298cc8e7558df43a to before 5c87b47374682f69686068ad0a7779365a527b1c` (git)
  - affected: `d34e6b175e61821026893ec5298cc8e7558df43a to before f1edbed787ba67988ed34e0132ca128b052b6ce8` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `2.6.32`
  - unaffected: `before 2.6.32` (semver)
  - unaffected: `5.10.261 to 5.10.*, inclusive` (semver)
  - unaffected: `5.15.212 to 5.15.*, inclusive` (semver)
  - unaffected: `6.1.178 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.145 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.95 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.38 to 6.18.*, inclusive` (semver)
  - unaffected: `7.1.3 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

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

- **CISA KEV:** Not listed.
- **EPSS:** 0.0016, the 4th percentile, on 15 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 19 Jul 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-63806](https://www.cve.org/CVERecord?id=CVE-2026-63806)
- [NVD: CVE-2026-63806](https://nvd.nist.gov/vuln/detail/CVE-2026-63806)

### References from the CNA

- <https://git.kernel.org/stable/c/2426c15c1395b7d5ccf1e5025ca898af7f3decb6>
- <https://git.kernel.org/stable/c/4186c850789906b875a1d263377a4d37c078e317>
- <https://git.kernel.org/stable/c/36ff44fb3d89960391e013fb9d91e23dbc48be47>
- <https://git.kernel.org/stable/c/92fc631b69deb1c7d56aec2663003600799dcd75>
- <https://git.kernel.org/stable/c/bf89e3738480d33cd515b4a18900e8443d40cd2e>
- <https://git.kernel.org/stable/c/5da9b1a87ec7cc3489c27016313524769f12d9e0>
- <https://git.kernel.org/stable/c/5c87b47374682f69686068ad0a7779365a527b1c>
- <https://git.kernel.org/stable/c/f1edbed787ba67988ed34e0132ca128b052b6ce8>

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-2026-63806>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-63806/>. Everything for agents: <https://agentprime.io/llms.txt>.