CVE-2026-33824
CVE-2026-33824 is a security flaw in Microsoft Internet Key Exchange (IKE) Service Extensions. Attackers can run their own code on Microsoft Internet Key Exchange (IKE) Service Extensions. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 18 Aug 2026.[1]
Microsoft Internet Key Exchange (IKE) Service Extensions is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Fixed in version 10.0.14393.9060, 10.0.17763.8644, 10.0.19044.7184 and 10.0.19045.7184 and others.
Description
CISA calls it a double free in Microsoft Internet Key Exchange (IKE) Service Extensions. In its words: “Microsoft Internet Key Exchange (IKE) Service Extensions contains a double free vulnerability that could enable remote code execution.”[1]
The underlying weakness is CWE-415, in MITRE’s list of common software weaknesses.[2]
It scores 9.8 out of 10 on the Common Vulnerability Scoring System, which rates it critical, scored by the organisation that published the CVE using CVSS 3.1.[2]
Affected versions
NVD’s record lists these fixed versions: in each line, everything before the version shown is affected.[2]
| Product | Fixed in |
|---|---|
| Windows 10 Version 1607 | 10.0.14393.9060 |
| Windows 10 Version 1809 | 10.0.17763.8644 |
| Windows 10 Version 21H2 | 10.0.19044.7184 |
| Windows 10 Version 22H2 | 10.0.19045.7184 |
| Windows 11 version 23H2 | 10.0.22631.6936 |
| Windows 11 Version 23H2 | 10.0.22631.6936 |
| Windows 11 Version 24H2 | 10.0.26100.8246 |
| Windows 11 Version 25H2 | 10.0.26200.8246 |
Most families won’t have Microsoft Internet Key Exchange (IKE) Service Extensions; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 18 Aug 2026, 126 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 21 Aug 2026 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 77%. That’s in the top 1% of the flaws it scores.[4]
CISA assesses it as automatable: attackers can run it against many targets at once.
CISA doesn’t say who was attacked, or how.
Fix
Microsoft has published a fix or advice.[3] 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).”[1]
- Check whether you use it.Microsoft Internet Key Exchange (IKE) Service Extensions is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
- Send this page to your IT person.Ask them to confirm it’s fixed (fixed in version 10.0.14393.9060, 10.0.17763.8644, 10.0.19044.7184 and 10.0.19045.7184 and others), or not in use. CISA gave US government agencies until 21 Aug 2026 to fix it.
- If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.
You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 9.8.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 77%.[4] |
See also
Other Microsoft flaws
- CVE-2026-96951, Microsoft Windows: command injection ·
- CVE-2026-65660, Microsoft SharePoint: code injection ·
- CVE-2026-85880, Microsoft Windows: heap-based buffer overflow ·
- CVE-2026-81963, Microsoft Windows: link following ·
- CVE-2019-1068, Microsoft SQL Server: remote code execution ·
Similar flaws
- CVE-2018-4990, Adobe Acrobat and Reader: double free ·
- CVE-2021-22600, Linux Kernel: privilege escalation ·
- CVE-2020-9859, Apple devices: code execution ·
Added the same day
- CVE-2026-65400, Apple macOS: improper authentication ·
- CVE-2026-59310, Broadcom VMware vCenter: path traversal ·
- CVE-2026-55040, Microsoft SharePoint: weak authentication ·
Every Microsoft flaw on CISA’s list · Everything added in August 2026
References
- ^ Cybersecurity and Infrastructure Security Agency. “Microsoft Internet Key Exchange (IKE) Service Extensions Double Free Vulnerability”. Known Exploited Vulnerabilities Catalog, added 18 Aug 2026.
- ^ National Institute of Standards and Technology. “CVE-2026-33824 Detail”. National Vulnerability Database, published 14 Apr 2026.
- ^ Microsoft. Advisories and fixes: msrc.microsoft.com, msrc.microsoft.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.771, percentile 99.6, 31 Oct 2026.
- CVE Program. “CVE-2026-33824”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.