PatchTheCVECVE-2026-68820: Microsoft Windows Ancillary Function Driver for WinSock Use-After-Free Vulnerability
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HIGH 7.0EXPLOITEDWATCHLISTUPGRADEUPGRADEUPGRADE
CVE-2026-68820 is a high-severity flaw (CVSS 7.0) affecting windows 10 1607, windows 10 1809, windows 10 21h2, reported as exploited in the wild. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Use after free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.
Why this priority
- High severity
- Exploited in the wild (CISA KEV)
- On your watchlist
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.0 (High) |
| Attack vector | Local |
| Attack complexity | High |
| Privileges needed | Low |
| User interaction | None |
| EPSS exploit chance | 0.3% (top 74%) |
| CISA exploited list | Yes, fix due 2026-08-25 |
| Weakness | CWE-416 |
| Published | 2026-08-11 |
| Last modified | 2026-10-26 |
Publisher (CNA): Microsoft Corporation · Vendor: microsoft
Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Exploited Added to the CISA Known Exploited Vulnerabilities list
- Published CVE record published
- Deadline CISA due date for US federal agencies to patch
- Updated Record last modified
microsoft windows 10 1607 UPGRADE
Affected: < 10.0.14393.9418
Fixed in: 10.0.14393.9418
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
microsoft windows 10 1809 UPGRADE
Affected: < 10.0.17763.9115
Fixed in: 10.0.17763.9115
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
microsoft windows 10 21h2 UPGRADE
Affected: < 10.0.19044.7663
Fixed in: 10.0.19044.7663
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
microsoft windows 10 22h2 UPGRADE
Affected: < 10.0.19045.7663
Fixed in: 10.0.19045.7663
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
microsoft windows 11 23h2 UPGRADE
Affected: < 10.0.22631.7517
Fixed in: 10.0.22631.7517
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
microsoft windows 11 24h2 UPGRADE
Affected: < 10.0.26100.9106
Fixed in: 10.0.26100.9106
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
Exact fixes by distribution
Fedora 46 · flare-im · FIXED · 0.22.7-1.fc46 · FEDORA-2026-cd5e8062a1 · source
sudo dnf upgrade --advisory=FEDORA-2026-cd5e8062a1
Fedora ELN · libdnf · FIXED · 0.76.0-2.eln159 · FEDORA-2026-dbd263e9d4 · source
sudo dnf upgrade --advisory=FEDORA-2026-dbd263e9d4
Windows 10 Version 1809 for 32-bit Systems · KB5120238 · FIXED · 10.0.17763.9121 · KB5120238 · source
Install KB5120238 via Windows Update, then verify:
Get-HotFix -Id KB5120238
Windows 10 Version 1809 for x64-based Systems · KB5120238 · FIXED · 10.0.17763.9121 · KB5120238 · source
Install KB5120238 via Windows Update, then verify:
Get-HotFix -Id KB5120238
Install KB5120238 via Windows Update, then verify:
Get-HotFix -Id KB5120238
Windows Server 2019 (Server Core installation) · KB5120238 · FIXED · 10.0.17763.9121 · KB5120238 · source
Install KB5120238 via Windows Update, then verify:
Get-HotFix -Id KB5120238
Install KB5120242 via Windows Update, then verify:
Get-HotFix -Id KB5120242
Public exploits and detection
Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.
- GitHub PoC: ubitquity/Windows-WinSock-UAF-Mitigation (1 stars)
- GitHub PoC: fevar54/CVE-2026-68820-Mitigation-PoC- (1 stars)
- GitHub PoC: HORKimhab/CVE-2026-68820 (0 stars)
Verify at the official source NVD · CVE Program · CISA KEV catalog · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-68820?
windows 10 1607: upgrade to 10.0.14393.9418; windows 10 1809: upgrade to 10.0.17763.9115; windows 10 21h2: upgrade to 10.0.19044.7663. Exact commands for each OS are on this page.
Is CVE-2026-68820 being exploited?
Yes. CVE-2026-68820 is on the CISA Known Exploited Vulnerabilities list, so treat it as patch-now.
What does CVE-2026-68820 affect?
CVE-2026-68820 affects windows 10 1607, windows 10 1809, windows 10 21h2. Severity is high (CVSS 7.0). Use after free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.
How urgent is CVE-2026-68820?
Priority 61/100. High severity; Exploited in the wild (CISA KEV); On your watchlist
Software pages
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