voxell vciy
CVE-2021-34461: Windows Container Isolation FS Filter Driver Elevation of Privilege Vulnerability
ROUTINE
Telemetry drift only. No threshold crossed and no authority ruling changed.
CVE record, CISA KEV and EPSS as of 2026-10-18.
CVEs like this one computed, by meaning
What to do now held facts and links
- Upgrade to the fixed version for your release line, or later: 10.0.19041.1110; 10.0.19042.1110; 10.0.19043.1110 CVE record
- Record your decision, dated and frozen with today's evidence: patch by a date · mitigated by a compensating control · deferred · accepted the risk · not affected
- Check your version against the ranges this record publishes.
What it is stated by the CNA
Windows Container Isolation FS Filter Driver Elevation of Privilege Vulnerability
- weakness
- Elevation of Privilege
- affected
- Microsoft Windows 10 Version 2004; Microsoft Windows 10 Version 20H2; Microsoft Windows 10 Version 21H1; Microsoft Windows Server version 2004; Microsoft Windows Server version 20H2
- published ranges
- microsoft windows 10 20h2; microsoft windows 10 21h1; microsoft windows 10 2004; microsoft windows server 2016 20h2; and 1 more on the CVE page
- fixed in
- 10.0.19041.1110; 10.0.19042.1110; 10.0.19043.1110
- severity
- 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
- assigned by
- microsoft
- published
- 2021-07-16
check us msrc.microsoft.com
Exploit code held, dated
- exploit code
- None held in the PoC-in-GitHub feed. A public repository changes this brief.
What moved held, dated
| date | EPSS | event |
|---|---|---|
| 17 Jul 2021 | 0.00416 | |
| 23 Jul 2021 | 0.04557 | |
| 6 Jan 2022 | 0.17642 | crossed 0.10 |
| 4 Feb 2022 | 0.01372 | crossed 0.10 |
| 7 Mar 2023 | 0.00043 | scoring model v2023.03.01 |
| 17 Mar 2025 | 0.00158 | scoring model v2025.03.14 |
| 15 Apr 2026 | 0.00326 | |
| 1 May 2026 | 0.00316 | |
| 15 Jun 2026 | 0.00457 | scoring model v2026.06.15 |
| 11 Aug 2026 | 0.00525 |
20 observations held. A step marked with a scoring model moved because the measurement was replaced, not because the vulnerability changed.
Outside the record researched, cited
This section reads the record's references and adds cited findings from outside it. It needs an account. Everything above is held facts and is complete without it.
What would change this brief held, dated
- CISA KEV
- Not listed in the catalogue we hold. A listing changes this brief.
- exploit probability
- 0.01 on 2026-08-11 (FIRST's EPSS, a probability and not evidence of exploitation). Next band line: 10% (0.10). Crossing a line changes this brief.
- fix
- Held: 10.0.19041.1110; 10.0.19042.1110; 10.0.19043.1110. A newer fix from the CNA or OSV changes this brief.
How to check this
Every value above is held with two dates: when it was true upstream (as_of) and when we recorded it (tx_from). Re-derive the exploit probability as it stood on any date:
SELECT value, source, source_version, as_of, tx_from
FROM volatile_valid_as_of('CVE-2021-34461', '2026-10-30T23:59:59.999999Z', now());