CVE-2026-58634
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedUse after free in Desktop Window Manager allows an authorized attacker to elevate privileges locally.
In the news
Third-party coverage- Microsoft July 2026 Patch Tuesday fixes massive 570 flaws, 3 zero-days
- Microsoft CVE Summary - Bleeping Computer
Surfaced from public web coverage — external links open in a new tab.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceA use-after-free vulnerability in Windows Desktop Window Manager (dwm.exe) allows a locally authenticated attacker to corrupt memory and elevate privileges to SYSTEM level. The vulnerability involves the attacker causing the application to free memory and then accessing that freed memory region before the system reallocates it.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 10.0.28000.2525CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify Windows 11 build versionRun 'winver' from command prompt or check System Properties, or run 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"'Affected if The version shown is Windows 11 and the build number is below 10.0.28000.2525
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Confirm Windows 11 26h1 editionRun 'winver' - the "Version" field should show 26h1 or check Windows Settings > System > AboutAffected if The system shows Windows 11 version 26h1 with build lower than 2525
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Check dwm.exe is runningOpen Task Manager, go to Details tab, look for 'dwm.exe' in the list, or run 'tasklist | findstr dwm'Affected if dwm.exe is running (this is default on Windows 11) and the OS version matches affected builds
A system is affected if it runs Windows 11 version 26h1 with a build number lower than 10.0.28000.2525, as this is where the vulnerable dwm.exe version exists.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped10.0.28000.2525
Apply the Microsoft security update for CVE-2026-58634 when released. Prioritize deployment to systems with direct user access where untrusted local users could exploit this flaw.
Windows 11 26H1 build 28000.2525 or later
- Open Settings > Update & Security > Windows Update and check for updates.
- Install the latest cumulative update that includes the fix for CVE-2026-58634 (build 28000.2525 or later).
- Restart the computer to apply the update.
- Verify the OS build number is 10.0.28000.2525 or higher (run 'winver' or 'systeminfo').
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,560.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-58634 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-58634 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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