Secuno
ENNL
Book demo

CVE-2026-42904

Microsoft Windows 10 21h2 buffer overflow

9.6 CRITICALEPSS 0.53%
  1. Published9 Jun 2026

Description

Heap-based buffer overflow in Windows TCP/IP allows an unauthorized attacker to elevate privileges over an adjacent network.

CVSS 3.1 breakdown

Attack vectorAdjacent
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeChanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Affected products

Microsoft Windows 10 21h2< 10.0.19044.7417
Microsoft Windows 10 22h2< 10.0.19045.7417
Microsoft Windows 11 23h2< 10.0.22631.7219
Microsoft Windows 11 24h2< 10.0.26100.8655
Microsoft Windows 11 25h2< 10.0.26200.8655
Microsoft Windows 11 26h1< 10.0.28000.2269
Microsoft Windows Server 2022< 10.0.20348.5256
Microsoft Windows Server 2025< 10.0.26100.32995

Remediation

Fixed in
Microsoft Windows 10 21h2≥ 10.0.19044.7417
Microsoft Windows 10 22h2≥ 10.0.19045.7417
Microsoft Windows 11 23h2≥ 10.0.22631.7219
Microsoft Windows 11 24h2≥ 10.0.26100.8655
Microsoft Windows 11 25h2≥ 10.0.26200.8655
Microsoft Windows 11 26h1≥ 10.0.28000.2269
Microsoft Windows Server 2022≥ 10.0.20348.5256
Microsoft Windows Server 2025≥ 10.0.26100.32995

References

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

CVE-2026-148888.1
IBM DataPower Gateway 10.5.0.0 through 10.5.0.22, 10.6.1 through 10.6.6, 10.6.0.0…
CVE-2026-142699.8
IBM DataPower Gateway 10.5.0.0 through 10.5.0.22, 10.6.1 through 10.6.6, 10.6.0.0…
CVE-2026-764719.8
A vulnerability in the NX-API feature of Cisco NX-OS Software could allow an…
CVE-2026-465708.1
In NTFS-3G before 2026.7.7, a heap buffer overflow exists in ntfs_index_walk_down() in…
CVE-2026-1062928.3
Buffer overflow in Fonts in Google Chrome prior to 155.0.8059.39 allowed a remote…
CVE-2026-1062478.3
Buffer overflow in ANGLE in Google Chrome prior to 155.0.8059.39 allowed a remote…

Frequently asked

Is CVE-2026-42904 being actively exploited?

CVE-2026-42904 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.53%.

How severe is CVE-2026-42904?

CVE-2026-42904 has a CVSS 3.1 base score of 9.6, rated critical. EPSS estimates a 0.53% probability of exploitation.

Which products are affected by CVE-2026-42904?

Affected products include Microsoft Windows 10 21h2, Microsoft Windows 10 22h2, Microsoft Windows 11 23h2, Microsoft Windows 11 24h2, Microsoft Windows 11 25h2, and 3 more.

How do I fix CVE-2026-42904?

Upgrade affected software to a fixed version, for example Microsoft Windows 10 21h2 10.0.19044.7417, Microsoft Windows 10 22h2 10.0.19045.7417, Microsoft Windows 11 23h2 10.0.22631.7219 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-42904 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

See how prioritisation worksBook a demo

Get Patch this first every Monday

Five vulnerabilities that matter this week, ranked on real exploitation. Plain language, one email, no spam.

You can unsubscribe with one click from every issue. We handle your details as described in our privacy policy.

Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.