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CVE-2026-62817

HIGH 8.8 ALL-YEARS

Published 2026-08-11 · Last modified 2026-10-21 · microsoft · NVD: Analyzed

Out-of-bounds write in Windows DNS allows an unauthorized attacker to execute code over an adjacent network.

ELEVATED IMPACT

Severe if exploited (CVSS 8.8), but no confirmed exploitation. Patch on a normal cadence.

Exploitation likelihood

0.5%chance of exploitation in 30 days · 45th percentile

○ In CISA KEV○ Catalogued PoC◆ SSVC: exploitation none, automatable no

Impact if exploited

8.8CVSS 3.1 · HIGH · CNA

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityHigh

What an attacker needs

  • ⚠Access: Must sit on the same / adjacent network
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

No public PoC is currently catalogued.

Search for new PoCs

Search GitHub now — results may be empty or unverified.

Tracked sources are checked weekly for the full archive, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Affected

Vendors Microsoft

Products Windows Server 2019 Windows Server 2019 (Server Core Installation) Windows Server 2022 Windows Server 2025 Windows Server 2025 (Server Core Installation) Windows 10 1809 Windows 10 21h2 Windows 10 22h2 Windows 11 23h2 Windows 11 24h2 Windows 11 25h2 Windows 11 26h1

Weakness (CWE)

  • CWE-787: : Out-of-bounds Write

CVSS vector

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

References and research data (JSON)

Known Affected Software Configurations

VendorProductVersion range
MicrosoftWindows 10 1809< 10.0.17763.9121
MicrosoftWindows 10 1809< 10.0.17763.9121
MicrosoftWindows 10 21h2< 10.0.19044.7663
MicrosoftWindows 10 21h2< 10.0.19044.7663
MicrosoftWindows 10 21h2< 10.0.19044.7663
MicrosoftWindows 10 22h2< 10.0.19045.7663
MicrosoftWindows 10 22h2< 10.0.19045.7663
MicrosoftWindows 10 22h2< 10.0.19045.7663
MicrosoftWindows 11 23h2< 10.0.22631.7517
MicrosoftWindows 11 23h2< 10.0.22631.7517
MicrosoftWindows 11 24h2< 10.0.26100.9106
MicrosoftWindows 11 24h2< 10.0.26100.9106
MicrosoftWindows 11 25h2< 10.0.26200.9106
MicrosoftWindows 11 25h2< 10.0.26200.9106
MicrosoftWindows 11 26h1< 10.0.28000.2704
MicrosoftWindows 11 26h1< 10.0.28000.2704
MicrosoftWindows Server 2019< 10.0.17763.9121
MicrosoftWindows Server 2022< 10.0.20348.5440
MicrosoftWindows Server 2025< 10.0.26100.33222

All CVSS metrics

  • HIGH 8.8 v3.1 · CNA Primary
    CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
  • HIGH 8.8 v3.1 · NVD Secondary
    CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

Patches & mitigations

Advisories

Sources: NVD · CVE.org · All sources and attribution · EPSS