OnlyPatch
Windows IKE Extension

CVE-2022-21849 — Windows Internet Key Exchange (IKE) Protocol Extensions Remote Code Execution Vulnerability

Important CVSS 9.8 EPSS 0.06242 🔬 Patch diffed 2022-01 archive

Executive Summary

None

Overview

9.8
CVSS CRITICAL
Important
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
Category Remote Code Execution
Released Jan 11 2022
Last Updated Jan 11 2022
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.06242 — 0.92914 percentile
NVD CVSS 9.8 CRITICAL — matches MSRC

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
ATTACK VECTOR
Network
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
None
USER INTERACTION
None
SCOPE
Unchanged
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
High
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 8.5

EPSS Score

0.06242
probability of exploitation in the next 30 days
0.92914 percentile - updated 2026-08-14
View on FIRST.org

Affected Products

27 affected products
Product KB Article Severity Impact Restart Required
Windows 10 for 32-bit Systems 5009585 (Security Update) Important Remote Code Execution Yes
Windows 10 for x64-based Systems 5009585 (Security Update) Important Remote Code Execution Yes
Windows 10 Version 1607 for 32-bit Systems 5009546 (Security Update) Important Remote Code Execution Yes
Windows 10 Version 1607 for x64-based Systems 5009546 (Security Update) Important Remote Code Execution Yes
Windows 10 Version 1809 for 32-bit Systems 5009557 (Security Update) Important Remote Code Execution Yes
Windows 10 Version 1809 for ARM64-based Systems 5009557 (Security Update) Important Remote Code Execution Yes
Windows 10 Version 1809 for x64-based Systems 5009557 (Security Update) Important Remote Code Execution Yes
Windows 10 Version 1909 for 32-bit Systems 5009545 (Security Update) Important Remote Code Execution Yes
Windows 10 Version 1909 for ARM64-based Systems 5009545 (Security Update) Important Remote Code Execution Yes
Windows 10 Version 1909 for x64-based Systems 5009545 (Security Update) Important Remote Code Execution Yes
Windows 10 Version 20H2 for 32-bit Systems 5009543 (Security Update) Important Remote Code Execution Yes
Windows 10 Version 20H2 for ARM64-based Systems 5009543 (Security Update) Important Remote Code Execution Yes
Windows 10 Version 21H1 for 32-bit Systems 5009543 (Security Update) Important Remote Code Execution Yes
Windows 10 Version 21H1 for ARM64-based Systems 5009543 (Security Update) Important Remote Code Execution Yes
Windows 10 Version 21H1 for x64-based Systems 5009543 (Security Update) Important Remote Code Execution Yes
Windows 10 Version 21H2 for 32-bit Systems 5009543 (Security Update) Important Remote Code Execution Yes
Windows 10 Version 21H2 for ARM64-based Systems 5009543 (Security Update) Important Remote Code Execution Yes
Windows 10 Version 21H2 for x64-based Systems 5009543 (Security Update) Important Remote Code Execution Yes
Windows 11 version 21H2 for ARM64-based Systems 5009566 (Security Update) Important Remote Code Execution Yes
Windows 11 version 21H2 for x64-based Systems 5009566 (Security Update) Important Remote Code Execution Yes
Windows Server 2016 5009546 (Security Update) Important Remote Code Execution Yes
Windows Server 2016 (Server Core installation) 5009546 (Security Update) Important Remote Code Execution Yes
Windows Server 2019 5009557 (Security Update) Important Remote Code Execution Yes
Windows Server 2019 (Server Core installation) 5009557 (Security Update) Important Remote Code Execution Yes
Windows Server 2022 5009555 (Security Update) Important Remote Code Execution Yes
Windows Server 2022 (Server Core installation) 5009555 (Security Update) Important Remote Code Execution Yes
Windows Server, version 20H2 (Server Core Installation) 5009543 (Security Update) Important Remote Code Execution Yes

Patches

7 patches
Article Type Restart
5009585 Security Update Yes
5009546 Security Update Yes
5009557 Security Update Yes
5009545 Security Update Yes
5009543 Security Update Yes
5009566 Security Update Yes
5009555 Security Update Yes

Patch Diff

ghidriff · ikeext.dll (KB5009543)

Stack buffer overflow in Windows IKEv2 extension (ikeext.dll). IkeLookupVendorId handles vendorID 0x1000 by allocating v11-16 bytes from input, but IkeHandleSecurityRealmVendorId calls WfpBytesToString which copies data into an 80-byte stack buffer without length checking. Reachable via UDP/500 IKEv2 VendorID payload. Patch added length clamping.

Pre-patch version 10.0.22000.318
Post-patch version 10.0.22000.434
Function Address Change Note
IkeLookupVendorId modified Added length validation before allocating vendorID payload buffer
IkeHandleSecurityRealmVendorId modified Added length clamping before WfpBytesToString call to prevent stack buffer overflow
View full diff report View RCA report Download PoC

Attack Path

Pre-auth stack buffer overflow from an IKEv2 VendorID payload on UDP/500

Attack path for CVE-2022-21849 Pre-auth stack buffer overflow from an IKEv2 VendorID payload on UDP/500 01 — ENTRY Attacker sends an IKEv2 packet to UDP/500 Remote and pre-authentication - the IKE extension processes VendorID payloads before any credential check. 02 — CONTROLLED INPUT VendorID 0x1000 with an attacker-chosen payload length IkeLookupVendorId allocates v11-16 bytes based on the value taken from the packet. 03 — PATH The security-realm handler copies the payload into a fixed stack buffer IkeLookupVendorId -> IkeHandleSecurityRealmVendorId -> WfpBytesToString, destination is an 80-byte stack buffer. 04 — MISSING CHECK WfpBytesToString is called with no length check against the 80-byte destination The patch adds length validation in IkeLookupVendorId before the allocation and clamps the length before the WfpBytesToString call. 05 — PRIMITIVE Remote pre-auth kernel-adjacent stack overflow with attacker-controlled bytes Content comes directly off the wire, so this is a controlled overwrite rather than a zero-fill.

Derived from the patch delta: the checks added by the vendor identify which fields crossed a trust boundary unvalidated. Reachability and privilege are taken from the call chain in the RCA report.

Known Exploits

Acknowledgments

Polar Bear

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