CVE-2026-62795 Overview
CVE-2026-62795 is a use-after-free vulnerability [CWE-416] in the Windows Lightweight Directory Access Protocol (LDAP) implementation. The flaw allows an unauthorized attacker to execute arbitrary code over a network. Successful exploitation requires user interaction, but does not require prior authentication or elevated privileges on the target system.
The vulnerability affects a broad range of Microsoft Windows client and server releases, including Windows 10, Windows 11, and Windows Server versions from 2012 through 2025. Microsoft published a security advisory through the MSRC update guide.
Critical Impact
Remote attackers can trigger memory corruption in the Windows LDAP stack to gain code execution on affected systems, compromising confidentiality, integrity, and availability.
Affected Products
- Microsoft Windows 10 (versions 1607, 1809, 21H2, 22H2) across x86, x64, and ARM64
- Microsoft Windows 11 (versions 23H2, 24H2, 25H2, 26H1) across x64 and ARM64
- Microsoft Windows Server 2012, 2012 R2, 2016, 2019, 2022, and 2025
Discovery Timeline
- 2026-08-11 - CVE-2026-62795 published to NVD
- 2026-08-13 - Last updated in NVD database
Technical Details for CVE-2026-62795
Vulnerability Analysis
The vulnerability resides in the Windows LDAP client and server components responsible for processing LDAP protocol messages. A use-after-free condition occurs when the LDAP code path references a memory object that has already been freed. An attacker who controls the layout of the freed region can steer execution flow after the dangling pointer is dereferenced.
Exploitation requires the target user to initiate an action, such as connecting to an attacker-controlled LDAP endpoint or processing crafted LDAP responses. Because LDAP is central to Active Directory and directory-integrated applications, exposure spans both workstations querying directory services and servers hosting or relaying LDAP traffic. Successful exploitation yields code execution in the context of the vulnerable process, which frequently runs with elevated privileges on domain-joined systems.
Root Cause
The root cause is improper lifetime management of a heap-allocated object within the LDAP protocol handler. The code releases the object while another code path retains a reference. When that reference is later used to read a virtual function pointer or callback, the attacker-controlled contents of the reallocated memory direct execution.
Attack Vector
Attackers exploit the flaw over the network by inducing a victim to interact with a malicious LDAP server or by injecting crafted responses into an existing LDAP conversation. No credentials are required. The attacker typically pairs the memory corruption with heap grooming to place controlled data at the freed address before the reuse occurs. Refer to the Microsoft CVE-2026-62795 Update advisory for authoritative technical details.
Detection Methods for CVE-2026-62795
Indicators of Compromise
- Unexpected outbound LDAP or LDAPS connections (TCP/389, TCP/636, TCP/3268-3269) from workstations to non-domain-controller destinations.
- Crashes or abnormal terminations of wldap32.dll-linked processes recorded in Windows Error Reporting and Application event logs.
- Suspicious child processes spawned from services that consume LDAP, such as Group Policy or authentication brokers.
Detection Strategies
- Inspect LDAP traffic for malformed BER-encoded responses, oversized attribute values, or unexpected referral chains steering clients to untrusted servers.
- Correlate directory service query failures with subsequent process crashes on the querying host to surface exploitation attempts.
- Hunt for post-exploitation indicators such as unsigned DLL loads, credential access tooling, or lateral movement following LDAP client activity.
Monitoring Recommendations
- Enable Sysmon Event IDs 3 (network connect) and 10 (process access) with rules focused on LDAP client binaries.
- Forward Directory Service and System event logs from domain controllers and clients to a centralized analytics platform.
- Alert on new LDAP referrals crossing trust or network boundaries, especially referrals pointing to external IP space.
How to Mitigate CVE-2026-62795
Immediate Actions Required
- Apply the Microsoft security update referenced in the MSRC advisory for CVE-2026-62795 to all affected Windows client and server builds.
- Prioritize domain controllers, jump hosts, and privileged workstations that frequently initiate LDAP queries.
- Audit outbound LDAP egress and block traffic to untrusted networks at perimeter and host firewalls.
Patch Information
Microsoft has published fixed builds through the standard Windows Update and Microsoft Update Catalog channels. The advisory lists the update package required for each affected Windows 10, Windows 11, and Windows Server SKU. Administrators should validate the KB numbers against their servicing baseline and confirm deployment through Get-HotFix or configuration management reports.
Workarounds
- Restrict outbound LDAP and LDAPS connectivity so clients can only reach authorized domain controllers.
- Enforce LDAP channel binding and signing to reduce exposure from man-in-the-middle response injection.
- Segment sensitive systems from user networks to limit the ability of low-trust hosts to initiate LDAP requests to attacker-controlled endpoints.
# Verify the Windows LDAP patch is installed (replace KB number with the value from MSRC)
Get-HotFix | Where-Object { $_.HotFixID -eq "KBXXXXXXX" }
# Enforce LDAP signing on domain controllers via registry
reg add "HKLM\SYSTEM\CurrentControlSet\Services\NTDS\Parameters" /v LDAPServerIntegrity /t REG_DWORD /d 2 /f
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
