Vulnpedia
← All CVEs

CVE-2026-56165

CRITICAL 9.8 ALL-YEARS

Published 2026-07-23 · Last modified 2026-10-08 · microsoft · NVD: Analyzed

Heap-based buffer overflow in Microsoft Account allows an unauthorized attacker to execute code over a network.

ELEVATED IMPACT

Severe if exploited (CVSS 9.8), but no confirmed exploitation. Patch on a normal cadence.

Exploitation likelihood

1.0%chance of exploitation in 30 days · 62nd percentile

○ In CISA KEV○ Catalogued PoC◆ SSVC: exploitation none, automatable yes

Impact if exploited

9.8CVSS 3.1 · CRITICAL · CNA

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityHigh

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓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 Microsoft Account Account

Weakness (CWE)

  • CWE-122: : Heap-based Buffer Overflow

CVSS vector

CVSS:3.1/AV:N/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
MicrosoftAccount*

All CVSS metrics

  • CRITICAL 9.8 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
  • CRITICAL 9.8 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/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