EUVD-2026-73346
GHSA-763c-9mqj-7c38
Severity by source
AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Network-reachable heap overflow with no auth needed, but victim must initiate TLS contact; full impact to the hosting process justified.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
3DescriptionCVE.org
Heap-based buffer overflow in Windows Schannel allows an unauthorized attacker to execute code over a network.
AnalysisAI
Remote code execution is achievable in Windows Schannel - Microsoft's built-in TLS/SSL security package - through a heap-based buffer overflow triggered over a network connection. Affected builds span Windows 11 versions 23H2 through 26H1 and Windows Server 2022 and 2025, all prior to Microsoft's patched releases. …
Unlock full vulnerability intelligence
- Risk assessment & exploitation conditions
- Attack chain visualization
- Remediation with exact patch versions
- Threat intelligence from 22 sources
- Personal watchlist & email alerts
Free forever · No credit card required
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires that a user on an unpatched Windows system initiates a TLS connection to an attacker-controlled endpoint - satisfied by browsing to a malicious HTTPS URL, processing an attacker-supplied TLS stream via any Schannel-backed application, or being subjected to a TLS interception/redirect attack. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 8.8 score reflects a genuine high-severity posture: network-reachable, low complexity, no privileges required, and full C/I/A impact. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Apply Microsoft's released security update immediately, targeting the patched build numbers: Windows Server 2025 to 10.0.26100.33438 or later, Windows Server 2022 to 10.0.20348.5622 or later, Windows 11 26H1 to 10.0.28000.2954 or later, Windows 11 25H2 to 10.0.26200.9445 or later, Windows 11 24H2 to 10.0.26100.9445 or later, and Windows 11 23H2 to 10.0.22631.7582 or later - all via Windows Update or WSUS per normal patching cadence. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, audit all Windows 11 (23H2-26H1) and Windows Server 2022/2025 systems across the enterprise to establish exposure inventory and identify mission-critical systems requiring priority patching. …
Sign in for detailed remediation steps and compensating controls.
Threat intelligence, references, and detailed analysis are available after sign-in.
Same weakness CWE-122 – Heap-based Buffer Overflow
View allSame technique Buffer Overflow
View allShare
External POC / Exploit Code
Leaving vuln.today