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.NET EUVDEUVD-2026-29634

| CVE-2026-35433 HIGH
Improper Input Validation (CWE-20)
2026-05-12 microsoft GHSA-8x9c-mqxv-q2pp
7.3
CVSS 3.1 · Vendor: microsoft
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Craft malicious input for WPF app
  2. Delivery
    Deliver file to local user
  3. Exploit
    User opens crafted input
  4. Execution
    Trigger heap overflow in .NET runtime
  5. Impact
    Execute code and elevate privileges

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V2 - Validation and Business Logic Input validation, allowlisting
Exploitation Conditions

Exploitation requires local access to the target system and a targeted user to open or process attacker-controlled input in an application built on the affected .NET Windows Desktop/WPF runtime (UI:R in the CVSS vector). No prior authentication or elevated privileges are needed by the attacker (PR:N), but the mandatory user interaction and local-only vector (AV:L) are the key limiting factors - this cannot be triggered remotely over a network without a user opening the malicious content, and only Windows deployments running affected .NET 8.0/9.0/10.0 desktop runtime versions are exploitable.

Impact

Signals are mixed and point to a real but non-urgent priority. The CVSS 3.1 vector (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L, base 7.3 High) describes a local attack requiring user interaction but no prior privileges, with high confidentiality/integrity impact. CISA SSVC rates Exploitation as 'none' (no observed exploitation) and Automatable as 'no', while Technical Impact is 'total' - so severity of outcome is high but scalability and current exploitation are low. EPSS is low at 0.11% (30th percentile), consistent with the SSVC 'none' exploitation status, yet public POC/exploit code does exist (a GitHub gist), so capability is available even if active exploitation is not observed. Note a partial tension: the 'Authentication Bypass' tag suggests auth-bypass framing, but the CVSS scope is Unchanged and the described impact is local privilege elevation via memory corruption, not a remote auth bypass - treat the tag cautiously. Net: patch on a normal-to-prompt cycle; this is not a mass-exploitation network threat but is a credible local EoP with working exploit code.

Exploit ScenarioDerived

An attacker crafts malicious input (e.g., a file or data payload) processed by a vulnerable WPF/.NET desktop application and delivers it to a local user; when the user opens it, improper input validation triggers a heap-based buffer overflow that lets the attacker execute code and elevate privileges on the host. Publicly available exploit code (a GitHub gist) lowers the barrier to weaponization, though the local vector and required user interaction limit scale.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Jul 23, 2026

Local privilege elevation in Microsoft .NET (Windows Desktop/WPF runtime) for versions 8.0, 9.0, and 10.0 allows an attacker to run code at a higher privilege level after a targeted user opens crafted input. The root cause combines improper input validation (CWE-20) with a heap-based buffer overflow (CWE-122), yielding total technical impact per CISA SSVC. Publicly available exploit code exists, but the vulnerability is not in CISA KEV and EPSS is low (0.11%, 30th percentile), indicating no observed widespread exploitation to date.

RemediationAI

Vendor-released patch: upgrade to .NET 8.0.27, 9.0.16, or 10.0.8 (or later) as appropriate for your runtime, updating the affected Microsoft.WindowsDesktop.App.Runtime.win-arm64/x64/x86 NuGet packages and redeploying dependent WPF applications; apply the latest Windows/.NET servicing update from Microsoft. Consult https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-35433, the announcement at https://github.com/dotnet/announcements/issues/398, and the advisory https://github.com/dotnet/wpf/security/advisories/GHSA-8x9c-mqxv-q2pp. Because exploitation requires a user to open attacker-supplied input in an affected desktop application, where immediate patching is not possible reduce risk by restricting which untrusted files/inputs are opened by WPF/.NET desktop apps and by limiting execution to least-privilege user accounts to reduce the value of a local elevation; these controls reduce but do not eliminate exposure and may impact user workflows that legitimately open external files.

Affected VersionsENISA

.NET 10.0 10.0.0 <10.0.8
.NET 8.0 8.0.0 <8.0.27
.NET 9.0 9.0.0 <9.0.16

Affected Packages

nuget microsoft.windowsdesktop.app.runtime.win-arm64 fix: 8.0.27, 9.0.16, 10.0.8
nuget microsoft.windowsdesktop.app.runtime.win-x64 fix: 8.0.27, 9.0.16, 10.0.8
nuget microsoft.windowsdesktop.app.runtime.win-x86 fix: 8.0.27, 9.0.16, 10.0.8
euvd net_10_0 fix: 10.0.8
euvd net_8_0 fix: 8.0.27
euvd net_9_0 fix: 9.0.16

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 6 packages in nuget, euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The affected component is the Windows Desktop runtime shipped with .NET (the Microsoft.WindowsDesktop.App.Runtime.win-arm64/x64/x86 packages), which underpins WPF desktop applications; the security advisory is published under the dotnet/wpf repository. CPE data confirms the affected products are Microsoft .NET 8.0, 9.0, and 10.0 on Windows across all architectures. The weakness is classified as CWE-20 (Improper Input Validation) by NVD and additionally CWE-122 (Heap-based Buffer Overflow) by Microsoft's advisory, meaning attacker-controlled input is not properly validated before being processed into a heap buffer, allowing memory corruption that can be leveraged to elevate privileges locally.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (microsoft) PRIMARY 7.3 HIGH
AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L
ENISA EUVD HIGH
vuln.today AI 7.3 HIGH

Local vector and required user interaction to open crafted input (AV:L, UI:R); no attacker privileges needed (PR:N); memory corruption yields high C/I and partial availability impact.

3.1 AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L
4.0 AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N
Red Hat 7.3 HIGH

Primary rating from Vendor (microsoft).

CVSS VectorVendor: microsoft

Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
Low

DescriptionCVE.org

Improper input validation in .NET allows an unauthorized attacker to elevate privileges locally.

Executive ViewAI

Why It Matters

Microsoft .NET Windows Desktop Runtime versions 8.0 through 10.0 contain a privilege escalation vulnerability that allows local attackers to achieve system-level access by delivering crafted input to targeted users. While no widespread exploitation has been observed to date, publicly available exploit code exists and poses material risk to organizations with .NET-dependent desktop applications across the enterprise. Immediate patching is critical to prevent potential system compromise.

Business Impact: High
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.1%
Top 70% exploitable
Prevalence
High
widely deployed .NET/WPF runtime, but Windows desktop scope narrows footprint
Threat Intel
2
1 sources
Vendor Status
Publicly Disclosed:No
Exploited:No
Latest Software Release:Exploitation Unlikely
Exploit
POC
Public exploit code exists
Data Quality
9 sources
Confidence: High
EUVD NVD CVE.org EPSS Vulnrichment NCSC-NL GHSA MSRC Vendor GitHub VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC Yes
EPSS 0.1%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
None
System Exposure· derived
Small
Automatable
No
Human Impact
High
Technical Impact
Total

Priority Score

61
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +36
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: +5

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Vendor StatusVendor

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