Tag Archives: Winsock

August Microsoft Patch Tuesday

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August Microsoft Patch Tuesday

August Microsoft Patch Tuesday. A total of 401 vulnerabilities were addressed - 170 fewer than in July. One of the vulnerabilities is known to be actively exploited in the wild:

🔻 EoP - Windows Ancillary Function Driver for WinSock (CVE-2026-68820). A local attacker can exploit this vulnerability to gain SYSTEM-level privileges. There is a contradiction in Microsoft's description: the Exploit Code Maturity in CVSS is marked as "Unproven", while at the same time Microsoft states that the vulnerability is being exploited in the wild. 🤷‍♂️

Public exploits are available for two other vulnerabilities:

🔸 EoP - Windows User Profile Service (CVE-2026-62832). This vulnerability allows an authenticated attacker to elevate privileges to ADMINISTRATOR level. Rapid7 believes this vulnerability is related to the LegacyHive exploit, which was published on July 14.

🔸 EoP - Windows Kernel (CVE-2026-62737). This vulnerability allows an authenticated attacker to elevate privileges to SYSTEM level. An exploit has been publicly available since August 11.

Among the remaining vulnerabilities, the following stand out:

🔹 RCE - Windows DNS Server (CVE-2026-62878). This wormable vulnerability allows a remote unauthenticated attacker to execute code on a vulnerable server with elevated privileges. It is recommended to test and install the update as soon as possible, especially on Internet-facing DNS servers.

🔹 RCE - Windows Deployment Services TFTP Server (CVE-2026-62893). This vulnerability, discovered as part of the ZDI (Zero Day Initiative) program, allows an attacker to execute code without authentication or user interaction. TFTP has no authentication mechanism and is available remotely via UDP port 69. Any WDS server serving Windows Imaging Format (WIM) files via TFTP, which is the standard PXE boot scenario, is vulnerable. The issue results from the lack of validation of the existence of an object before performing operations on it. UDP port 69 should be blocked at the perimeter, but attackers could easily use this vulnerability for lateral movement within an organization. If you're using WDS for deployments, test and install this update quickly.

🔹 RCE - Windows DHCP Server (CVE-2026-62823). Successful exploitation of this vulnerability allows a remote unauthenticated attacker to execute arbitrary code from an adjacent network by sending a specially crafted packet that triggers a heap-based buffer overflow.

🔹 EoP - Microsoft Exchange (CVE-2026-62911). This vulnerability allows a remote authenticated attacker (with Privileges Required: Low according to CVSS) to gain control over the mailboxes of all Exchange users, send and read emails, and download attachments. This vulnerability was demonstrated at Pwn2Own Berlin. ZDI researchers provided Microsoft with working exploits.

🔹 RCE - Microsoft QUIC (CVE-2026-62815). This use-after-free vulnerability allows an unauthenticated attacker to execute arbitrary code on a target system by sending a specially crafted network packet. QUIC is an IETF-standardized transport protocol that runs over UDP instead of TCP and serves as the foundation for HTTP/3. The protocol is used by approximately 13.5 million websites.

🔹 Tampering - Windows Container Isolation FS Filter Driver (unionfs.sys) (CVE-2026-72971). This vulnerability reportedly allows an attacker to overwrite certain files. As a result, an attacker could perform an action within a container that could impact the host system.

🗒 Full Vulristics report

April Microsoft Patch Tuesday

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April Microsoft Patch Tuesday

April Microsoft Patch Tuesday. A total of 167 vulnerabilities, about twice as many as in March. There is one vulnerability already being exploited in the wild:

🔻 Spoofing - Microsoft SharePoint Server (CVE-2026-32201). ZDI experts say "Spoofing bugs in SharePoint often manifest as cross-site scripting (XSS) bugs". "An attacker who successfully exploited the vulnerability could view some sensitive information (Confidentiality), make changes to disclosed information (Integrity), but cannot limit access to the resource (Availability)". There is no info yet about how widely it is being used in attacks, but you should not delay patching, especially if SharePoint is exposed to the Internet.

Formally, there are no public exploits yet. However, there are strong indications that a public exploit may already exist for one vulnerability.

🔸 EoP - Microsoft Defender (CVE-2026-33825). "Insufficient granularity of access control" in Microsoft Defender allows a logged-in attacker to gain higher privileges on a local system. Tenable and ZDI say the bug looks similar to the BlueHammer zero-day, for which a public exploit was released on GitHub on April 3. The researcher who published it, Chaotic Eclipse, criticized Microsoft’s disclosure process. ZDI says the exploit is real, but exploitation is unstable and not always reliable.

Other important issues:

🔹 RCE - Windows Active Directory (CVE-2026-33826). To exploit this, the attacker must have an account. The attacker sends a specially crafted RPC request to a vulnerable server, which can lead to code execution. Microsoft says the attacker must be in the same restricted Active Directory domain as the target system.

🔹 RCE - Windows Internet Key Exchange (IKE) Service Extensions (CVE-2026-33824). ZDI says this vulnerability is wormable, meaning it could allow malware to spread automatically between systems. It affects systems with IKE enabled, which creates a large attack surface. Microsoft recommends blocking UDP ports 500 and 4500 at the network edge. However, attackers inside the network can still use it for lateral movement. Patch quickly if you use IKE.

🔹 RCE - Windows TCP/IP (CVE-2026-33827). ZDI also says this may be wormable, especially on systems using IPv6 and IPSec. A race condition makes it harder to exploit, but similar bugs are often exploited at Pwn2Own, so you should not rely on that difficulty. If you use IPv6, test and deploy the patch quickly before exploits appear.

🔹 EoP - Windows Push Notifications (CVE-2026-26167). This Patch Tuesday includes several sandbox escape vulnerabilities, including in Push Notifications, AFD for Winsock, Windows Management Services, and User Interface Core. CVE-2026-26167 (Push Notifications) is the most important because it is the only one with low attack complexity. The others require winning a race condition (AC:H).

🔹 Spoofing - Remote Desktop (CVE-2026-26151). Weak warnings in the Remote Desktop interface allow a network attacker to trick a user into opening a specially crafted file, leading to spoofing. The issue was found by the UK National Cyber Security Centre (NCSC).

🗒 Full Vulristics report