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Windows Error Reporting CVE-2026-69482

| EUVDEUVD-2026-73516 HIGH
Creation of Temporary File in Directory with Insecure Permissions (CWE-379)
2026-09-08 secure@microsoft.com GHSA-95p3-2r4g-hwp8
7.1
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
    Gain low-privilege local session
  2. Delivery
    Enumerate WER temporary directory path
  3. Exploit
    Pre-place symlink targeting sensitive file or attacker path
  4. Execution
    Trigger or await crash event activating WER
  5. Persist
    WER follows symlink, writing/reading via attacker-controlled target
  6. Impact
    Read disclosed crash data or leverage misdirected write for privilege escalation

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V5 - File Handling Temp file permissions
Exploitation Conditions

Exploitation requires a local, authenticated session with at minimum a standard (low-privilege) user account on the affected Windows system - remote unauthenticated exploitation is not possible given AV:L/PR:L. The attacker must be able to enumerate or predict the WER temporary directory path and create symlinks or directory entries within it, which is possible for any normal user account on affected builds. No special application configuration, non-default feature enablement, or elevated rights are required beyond having an interactive or remote-desktop session. What limits exploitation: the attacker must already have local code execution as a low-privileged user, making this a post-compromise escalation primitive rather than an initial-access vector; exploitation is also constrained to moments when WER is actively processing a crash report.

Impact

The CVSS vector (AV:L/AC:L/PR:L/UI:N) accurately describes a local, low-complexity attack requiring only a standard user account - attack complexity is genuinely low because symlink races against WER temp-file creation are mechanistically straightforward on Windows. The combined C:H/I:H impact reflects the dual risk: an attacker can both read sensitive crash-dump fragments and redirect WER output writes to arbitrary locations, potentially enabling privilege escalation chains. EPSS data was not provided in the source intelligence, but given the local-only attack vector and the need for an existing user account, the realistic exploitation window is constrained to insider threats, post-compromise lateral movement, or situations where an adversary already has a foothold with low-privilege access. The wide affected-version spread - from Windows Server 2016 through Windows 11 26H1 - means the patch surface is large, and any Windows environment running unpatched builds across this range is exposed. No public exploit code and no CISA KEV listing further indicate that opportunistic mass exploitation is not occurring at time of analysis, though the straightforward attack complexity means a functional exploit could be developed quickly. The availability of a vendor patch makes remediation the priority over compensating controls.

Exploit ScenarioDerived

A standard domain user on a multi-user Windows system monitors the WER temporary directory and pre-creates a symlink or junction pointing to a sensitive system file or attacker-controlled path. When WER next processes a crash report, it follows the symlink, either writing crash-dump fragments to the attacker's chosen location or exposing sensitive data held in the temp file to the unprivileged user. No public exploit code has been identified at time of analysis, but the attack mechanics are well-understood from prior CWE-379 disclosures on Windows.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.3% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 09, 2026

Windows Error Reporting (WER) across a broad range of Windows 10, Windows 11, and Windows Server releases creates temporary files in directories with insecure permissions, enabling a local attacker with standard user privileges to tamper with those files and read their contents. The vulnerability is classified as CWE-379 and carries a CVSS 3.1 score of 7.1 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N), reflecting high confidentiality and integrity impact achievable without elevated rights. No public exploit code has been identified at time of analysis, and Microsoft has released patches through its standard update channel.

RemediationAI

Apply the Microsoft-released patches for the applicable Windows version via Windows Update or WSUS, targeting the fix build numbers listed in the affected-products section. The vendor advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-69482 provides the definitive patch mapping. For environments where immediate patching is not possible, restrict interactive logon access so that only trusted accounts can run processes on affected systems, reducing the pool of potential attackers. Additionally, auditing the permissions of directories used by WER (typically under %LOCALAPPDATA%\Microsoft\Windows\WER) and tightening ACLs to prevent world-writable entries can reduce the exploitability window, though this may require group policy enforcement and should be tested for WER functional impact. Disabling Windows Error Reporting entirely via Group Policy (Computer Configuration > Administrative Templates > Windows Components > Windows Error Reporting > Disable Windows Error Reporting) eliminates the attack surface at the cost of losing crash telemetry, which may impair incident response and vendor support interactions.

Affected VersionsENISA

Windows Server 2019 (Server Core installation) 10.0.17763.0 <10.0.17763.9245
Windows Server 2025 10.0.26100.0 <10.0.26100.33438
Windows 10 Version 22H2 10.0.19045.0 <10.0.19045.7725
Windows 10 Version 1607 10.0.14393.0 <10.0.14393.9512
Windows Server 2019 10.0.17763.0 <10.0.17763.9245
Windows 11 Version 24H2 10.0.26100.0 <10.0.26100.9445
Windows Server 2025 (Server Core installation) 10.0.26100.0 <10.0.26100.33438
Windows 11 Version 25H2 10.0.26200.0 <10.0.26200.9445
Windows 10 Version 1809 10.0.17763.0 <10.0.17763.9245
Windows 11 Version 23H2 10.0.22631.0 <10.0.22631.7582
Windows Server 2016 10.0.14393.0 <10.0.14393.9512
Windows Server 2022 10.0.20348.0 <10.0.20348.5622
Windows 10 Version 21H2 10.0.19044.0 <10.0.19044.7725
Windows 11 version 26H1 10.0.28000.0 <10.0.28000.2954
Windows Server 2016 (Server Core installation) 10.0.14393.0 <10.0.14393.9512

Affected Packages

euvd windows_10_version_1607 fix: 10.0.14393.9512
euvd windows_10_version_1809 fix: 10.0.17763.9245
euvd windows_10_version_21h2 fix: 10.0.19044.7725
euvd windows_10_version_22h2 fix: 10.0.19045.7725
euvd windows_11_version_23h2 fix: 10.0.22631.7582
euvd windows_11_version_24h2 fix: 10.0.26100.9445
euvd windows_11_version_25h2 fix: 10.0.26200.9445
euvd windows_11_version_26h1 fix: 10.0.28000.2954
euvd windows_server_2016 fix: 10.0.14393.9512
euvd windows_server_2016_server_core_installation fix: 10.0.14393.9512
euvd windows_server_2019 fix: 10.0.17763.9245
euvd windows_server_2019_server_core_installation fix: 10.0.17763.9245
euvd windows_server_2022 fix: 10.0.20348.5622
euvd windows_server_2025 fix: 10.0.26100.33438
euvd windows_server_2025_server_core_installation fix: 10.0.26100.33438

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 15 packages in euvd

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

Technical ContextAI · show details

Windows Error Reporting is the OS-level crash telemetry subsystem present in all modern Windows releases. CWE-379 describes the root cause: the application writes temporary files to a directory whose access-control list permits unprivileged users to create or modify directory entries (e.g., world-writable or user-writable paths). A classic exploitation path is a symlink or hard-link attack: a low-privileged attacker pre-positions a symlink in the target directory before WER creates its temp file, causing WER to follow the link and either expose sensitive crash-dump content (C:H) or write data to an attacker-chosen path (I:H). Affected CPE ranges span Windows 10 (versions 1607/1809/21H2/22H2), Windows 11 (versions 23H2/24H2/25H2/26H1), Windows Server 2016, 2019, 2022, and 2025, all in both full-installation and Server Core configurations.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (microsoft) PRIMARY 7.1 HIGH
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
vuln.today AI 7.1 HIGH

Local attack requiring only a standard user account; symlink race is low complexity; no availability impact since WER temp file tampering does not crash the system.

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

Primary rating from Vendor (microsoft).

CVSS VectorVendor: microsoft

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

Lifecycle Timeline

2
Patch available
Sep 08, 2026 - 18:35 EUVD
CVE Published
Sep 08, 2026 - 18:19 nvd
HIGH 7.1

DescriptionCVE.org

Creation of temporary file in directory with insecure permissions in Windows Error Reporting allows an authorized attacker to perform tampering locally.

Executive ViewAI

Why It Matters

Windows Error Reporting (WER) in Windows 10, Windows 11, and Windows Server contains a local privilege escalation vulnerability that allows standard users to read sensitive crash data and modify system diagnostics without administrative privileges. This exposes confidential information across the installed base and creates an insider threat vector for attackers already present on the network to escalate access or exfiltrate data.

Business Impact: High
Compensating Controls

Apply vendor patch. Pending patch deployment, interim mitigations include: restrict standard user write permissions to %LOCALAPPDATA%\Microsoft\Windows\WER directories via Group Policy, disable WER functionality on systems where diagnostics are not required, and implement file system monitoring on WER temporary directories to detect unauthorized access attempts.

Threat Intelligence Overview

EPSS Score
0.3%
Top 76% exploitable
Prevalence
Ubiquitous
Windows OS present in the vast majority of enterprise environments
Vendor Status
Publicly Disclosed:No
Exploited:No
Latest Software Release:Exploitation Unlikely
Data Quality
5 sources
Confidence: Medium

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 No
EPSS 0.3%
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
Defer
Exploitation
None
System Exposure· derived
Small
Automatable
No
Human Impact
High
Technical Impact
Total

Priority Score

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