EUVD-2026-44000
GHSA-cmjw-3xhh-prg6
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Unauthenticated remote packet to the IKE listener (AV:N/AC:L/PR:N/UI:N) causes a crash with availability-only impact (A:H) and no C/I loss.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Heap-based buffer overflow in Windows Internet Key Exchange (IKE) Protocol allows an unauthorized attacker to deny service over a network.
AnalysisAI
Network denial of service in the Windows Internet Key Exchange (IKE) protocol implementation allows an unauthenticated remote attacker to crash affected systems by triggering a heap-based buffer overflow. All impact is to availability only (CVSS 7.5, A:H, no confidentiality or integrity loss), making this a reliability/uptime threat against IPsec/VPN-facing Windows 10, Windows 11, and Windows Server hosts rather than a code-execution vulnerability. There is no public exploit identified at time of analysis and it is not listed in CISA KEV, but the low attack complexity and lack of authentication make it a meaningful patching priority for internet-exposed IPsec endpoints.
Technical ContextAI
The flaw resides in Windows' IKE protocol handler, the component responsible for negotiating IPsec security associations (Phase 1/Phase 2 key exchange) used by Windows VPN and site-to-site IPsec tunnels, which listens on UDP/500 and UDP/4500 (NAT-T). The root cause is CWE-122, a heap-based buffer overflow, meaning attacker-controlled data in a crafted IKE negotiation packet is written past the bounds of a dynamically allocated heap buffer. Because the corruption occurs in a kernel/service-level network daemon parsing untrusted IKE payloads, an out-of-bounds write corrupts heap metadata or adjacent allocations and causes the service or system to crash. Per the CPE data the vulnerable code ships across the mainstream Windows codebase - Windows 10 (1809, 21H2, 22H2), Windows 11 (24H2, 25H2, 26H1), and Windows Server 2019/2022/2025 including Server Core installs.
RemediationAI
Apply the Microsoft security update for CVE-2026-50696; Patch available per vendor advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50696, where the exact fixed build per Windows SKU is listed (no single cross-SKU version string is provided in the input, so consult the advisory for your specific edition). Until patching is complete, reduce exposure by restricting inbound UDP/500 and UDP/4500 (IKE and NAT-T) to known IPsec peer addresses at the perimeter firewall, which blocks the remote attack path but will break IPsec/VPN connectivity from any non-whitelisted peer; on hosts that do not use IPsec, disabling the IKEEXT (IKE and AuthIP IPsec Keying Modules) service removes the attack surface entirely but will disable IPsec-based VPNs and policies, so verify no dependent tunnels exist before doing so.
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Same weakness CWE-122 – Heap-based Buffer Overflow
View allSame technique Buffer Overflow
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External POC / Exploit Code
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