# vsock: treat TCP_CLOSING as once-established

CVE record · `CVE-2026-99213`

- **Identifiers:** `CVE-2026-99213`
- **State:** Confirmed
- **Severity:** CVSS 7.8 High
- **Critical:** No
- **CNA:** Linux
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 28 Oct 2026
- **Updated:** 31 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 28 Oct 2026, 10:36 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: `d021c344051af91f42c5ba9fdedc176740cbd238 to before ea36ef3c229d54b552432d1290aee1d807f67fd5` (git)
  - affected: `d021c344051af91f42c5ba9fdedc176740cbd238 to before 5f2ab77028602a22f0cc33cac063a313787cbeae` (git)
  - affected: `d021c344051af91f42c5ba9fdedc176740cbd238 to before f89770c7365748d9d6a2ae07d1c23497ca21ec07` (git)
  - affected: `d021c344051af91f42c5ba9fdedc176740cbd238 to before deb972c7eea8d0bc3109c35c30a1c86d4939f811` (git)
  - affected: `d021c344051af91f42c5ba9fdedc176740cbd238 to before baf1b5715640e434249ce7f63f94bd1a00938ef9` (git)
  - affected: `d021c344051af91f42c5ba9fdedc176740cbd238 to before c2c5359ef2c33684fa3f3652fd761a483db8d1e7` (git)
  - affected: `d021c344051af91f42c5ba9fdedc176740cbd238 to before 44d1ca05d6094a5d75c671a0545249186d790b8d` (git)
  - affected: `d021c344051af91f42c5ba9fdedc176740cbd238 to before 4f6ac74fa594a918d41255c941256e1d51592d3b` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `3.9`
  - unaffected: `before 3.9` (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: `6.6.161 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.115 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.59 to 6.18.*, inclusive` (semver)
  - unaffected: `7.2.13 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

- 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

- 28 Oct 2026, 10:36 UTC: [Confirmed by the CVE List](https://www.cve.org/CVERecord?id=CVE-2026-99213)

## Sources

- [CVE List: CVE-2026-99213](https://www.cve.org/CVERecord?id=CVE-2026-99213)
- [NVD: CVE-2026-99213](https://nvd.nist.gov/vuln/detail/CVE-2026-99213)

### References from the CNA

- <https://git.kernel.org/stable/c/ea36ef3c229d54b552432d1290aee1d807f67fd5>
- <https://git.kernel.org/stable/c/5f2ab77028602a22f0cc33cac063a313787cbeae>
- <https://git.kernel.org/stable/c/f89770c7365748d9d6a2ae07d1c23497ca21ec07>
- <https://git.kernel.org/stable/c/deb972c7eea8d0bc3109c35c30a1c86d4939f811>
- <https://git.kernel.org/stable/c/baf1b5715640e434249ce7f63f94bd1a00938ef9>
- <https://git.kernel.org/stable/c/c2c5359ef2c33684fa3f3652fd761a483db8d1e7>
- <https://git.kernel.org/stable/c/44d1ca05d6094a5d75c671a0545249186d790b8d>
- <https://git.kernel.org/stable/c/4f6ac74fa594a918d41255c941256e1d51592d3b>

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-2026-99213>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-99213/>. Everything for agents: <https://agentprime.io/llms.txt>.