CVE-2026-34348

Windows Event Logging Service Information Disclosure Vulnerability

Published Jul 14, 2026 CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
Description
Protection mechanism failure in Windows Event Logging Service allows an authorized attacker to disclose information over a network.

Analysis

AI-generated

Technical impact

A protection mechanism failure in Windows Event Logging Service permits an authorized attacker to disclose system event data over the network. The vulnerability, identified as CWE‑693, enables the attacker to gain information about system configuration, operations or potentially sensitive log content, without altering system state or executing code. The impact is confined to the confidentiality of the disclosed information, with no known denial of service or intrusion persistence.

Affected Systems

The flaw affects several Microsoft Windows releases including Windows 10 versions 1809, 21H2, and 22H2; Windows 11 versions 23H2, 24H2, 25H2, 26H1; and Windows Server 2019, Server 2022, and Server 2025, both full and core installations.

Risk and Exploitability

The CVSS score of 6.5 indicates a moderate severity, while the EPSS score of less than 1 % suggests a very low likelihood of exploitation at present. Since KEV lists the vulnerability as not currently exploited, the overall risk remains moderate. The attack requires an attacker to have authorized access, but the input does not specify whether this access is local or remote; it is inferred that local privileged access is the likely scenario to trigger the event log transmission over the network. No remote exploitation vector is documented, and no public exploit code is known.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Apply the security update for CVE‑2026‑34348 through Microsoft Update or the Windows Update Catalog.
  • Restart the Windows Event Log Service to ensure the updated components are loaded.
  • Apply firewall or network segmentation rules to restrict outbound event log traffic to trusted audit destinations.

Generated by OpenCVE AI on July 31, 2026 at 09:03 UTC.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Microsoft windows Server 2019 (server Core Installation)
Microsoft windows Server 2025 (server Core Installation)
Vendors & Products Microsoft windows Server 2019 (server Core Installation)
Microsoft windows Server 2025 (server Core Installation)
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Protection mechanism failure in Windows Event Logging Service allows an authorized attacker to disclose information over a network.
Title Windows Event Logging Service Information Disclosure Vulnerability
First Time appeared Microsoft
Microsoft windows 10 1809
Microsoft windows 10 21h2
Microsoft windows 10 22h2
Microsoft windows 11 23h2
Microsoft windows 11 24h2
Microsoft windows 11 25h2
Microsoft windows 11 26h1
Microsoft windows Server 2019
Microsoft windows Server 2022
Microsoft windows Server 2025
Weaknesses CWE-693
CPEs cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_21H2:*:*:*:*:*:*:x86:*
cpe:2.3:o:microsoft:windows_10_22H2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_23H2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_23H2:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_11_24H2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_25H2:*:*:*:*:*:*:arm64:*
cpe:2.3:o:microsoft:windows_11_26H1:*:*:*:*:*:*:x64:*
cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:*
Vendors & Products Microsoft
Microsoft windows 10 1809
Microsoft windows 10 21h2
Microsoft windows 10 22h2
Microsoft windows 11 23h2
Microsoft windows 11 24h2
Microsoft windows 11 25h2
Microsoft windows 11 26h1
Microsoft windows Server 2019
Microsoft windows Server 2022
Microsoft windows Server 2025
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C'}