CyberSecBulletin
CVE-2026-33824Exploited in the wildNVD status: Analyzed

Microsoft Internet Key Exchange (IKE) Service Extensions Double Free

Published Updated By the CyberSecBulletin desk

CVE-2026-33824 is a critical-severity double free vulnerability in Windows 10 Version 1607 from Microsoft, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 10.0.14393.9060 as the first without the flaw, so updating Windows 10 Version 1607 to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on August 18, 2026, which means attacks have been observed in the wild.

Patch now

Attackers are already exploiting this vulnerability, according to CISA.

What to do

  1. Update Windows 10 Version 1607 to 10.0.14393.9060 or a later version.
  2. Update Windows 10 Version 1809 to 10.0.17763.8644 or a later version.
  3. Update Windows 10 Version 21H2 to 10.0.19044.7184 or a later version.
  4. CISA's required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
  5. Read the advisory on msrc.microsoft.com for workarounds and exact fixed builds.
  6. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
MicrosoftWindows 10 Version 160710.0.14393.0 up to, but not including, 10.0.14393.906010.0.14393.9060
MicrosoftWindows 10 Version 180910.0.17763.0 up to, but not including, 10.0.17763.864410.0.17763.8644
MicrosoftWindows 10 Version 21H210.0.19044.0 up to, but not including, 10.0.19044.718410.0.19044.7184
MicrosoftWindows 10 Version 22H210.0.19045.0 up to, but not including, 10.0.19045.718410.0.19045.7184
MicrosoftWindows 11 version 23H210.0.22631.0 up to, but not including, 10.0.22631.693610.0.22631.6936
MicrosoftWindows 11 Version 24H210.0.26100.0 up to, but not including, 10.0.26100.824610.0.26100.8246
MicrosoftWindows 11 Version 25H210.0.26200.0 up to, but not including, 10.0.26200.824610.0.26200.8246
MicrosoftWindows 11 version 26H110.0.28000.0 up to, but not including, 10.0.28000.183610.0.28000.1836
MicrosoftWindows Server 201610.0.14393.0 up to, but not including, 10.0.14393.906010.0.14393.9060
MicrosoftWindows Server 2016 (Server Core installation)10.0.14393.0 up to, but not including, 10.0.14393.906010.0.14393.9060
MicrosoftWindows Server 201910.0.17763.0 up to, but not including, 10.0.17763.864410.0.17763.8644
MicrosoftWindows Server 2019 (Server Core installation)10.0.17763.0 up to, but not including, 10.0.17763.864410.0.17763.8644
MicrosoftWindows Server 202210.0.20348.0 up to, but not including, 10.0.20348.502010.0.20348.5020
MicrosoftWindows Server 2022, 23H2 Edition (Server Core installation)10.0.25398.0 up to, but not including, 10.0.25398.227410.0.25398.2274
MicrosoftWindows Server 202510.0.26100.0 up to, but not including, 10.0.26100.3269010.0.26100.32690
MicrosoftWindows Server 2025 (Server Core installation)10.0.26100.0 up to, but not including, 10.0.26100.3269010.0.26100.32690
MicrosoftWindows 10 1607before 10.0.14393.906010.0.14393.9060
MicrosoftWindows 10 1809before 10.0.17763.864410.0.17763.8644
MicrosoftWindows 10 21h2before 10.0.19044.718410.0.19044.7184
MicrosoftWindows 10 22h2before 10.0.19045.718410.0.19045.7184
MicrosoftWindows 11 23h2before 10.0.22631.693610.0.22631.6936
MicrosoftWindows 11 24h2before 10.0.26100.824610.0.26100.8246
MicrosoftWindows 11 25h2before 10.0.26200.824610.0.26200.8246
MicrosoftWindows 11 26h1before 10.0.28000.183610.0.28000.1836
MicrosoftWindows Server 2022 23h2before 10.0.25398.227410.0.25398.2274

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (microsoft.com).

Official description

Double free in Windows IKE Extension allows an unauthorized attacker to execute code over a network.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Double Free

The product calls free() twice on the same memory address.

How developers prevent this class of flaw

  • Choose a language that provides automatic memory management.
  • Ensure that each allocation is freed only once. After freeing a chunk, set the pointer to NULL to ensure the pointer cannot be freed again. In complicated error conditions, be sure that clean-up routines respect the state of allocation properly. If the language is object oriented, ensure that object destructors delete each chunk of memory only once.
  • Use a static analysis tool to find double free instances.

More Double Free vulnerabilities (CWE-415)

Timeline

  1. CISA published its SSVC assessment (exploitation: active, automatable: yes, technical impact: total).
  2. CVE record published.
  3. Added to CISA's Known Exploited Vulnerabilities catalogue.
  4. Deadline for US federal agencies to remediate, set by CISA.
  5. Record last changed materially (score, affected products, status or references).

References

Recent Double Free vulnerabilities

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