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June "In the Trend of VM" (#28): Linux kernel, Microsoft Defender, and Palo Alto Networks device vulnerabilities

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June In the Trend of VM (#28): Linux kernel, Microsoft Defender, and Palo Alto Networks device vulnerabilities

June "In the Trend of VM" (#28): Linux kernel, Microsoft Defender, and Palo Alto Networks device vulnerabilities. Presenting the traditional monthly roundup of trending vulnerabilities according to Positive Technologies. In the previous May edition, we covered four vulnerabilities. This time, there are also four vulnerabilities associated with five CVE identifiers.

🗞 Post on Habr (rus)
🗒 Digest on the PT website (rus)

🔻 EoP - Linux Kernel "Dirty Frag" (CVE-2026-43284, CVE-2026-43500). A chain of vulnerabilities with a public exploit to obtain root access. There are signs of in-the-wild exploitation.

🔻 EoP - Linux Kernel "Fragnesia" (CVE-2026-46300). Another vulnerability for gaining root access with a public exploit.

🔻 EoP - Microsoft Defender "RedSun" (CVE-2026-41091). A privilege escalation vulnerability leading to SYSTEM-level access, with a public exploit available and indications of in-the-wild exploitation. Pay special attention to Windows server and desktop environments where Microsoft Defender is enabled but there is no Internet access for regular updates.

🔻 RCE - PAN-OS (CVE-2026-0300). An unauthenticated RCE with root privileges affecting PA-Series and VM-Series firewalls. A public exploit exists, and there are indications of in-the-wild exploitation.

🟥 The full list of trending vulnerabilities is available on the portal

June Microsoft Patch Tuesday

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June Microsoft Patch Tuesday

June Microsoft Patch Tuesday. Last week I was on vacation in Veliky Novgorod, so I'm publishing this overview only now. A total of 202 vulnerabilities were addressed, approximately twice as many as in May. There are currently no vulnerabilities marked as exploited in the wild. However, there are two vulnerabilities with publicly available exploits:

🔸 RCE - HTTP.sys (CVE-2026-47291). This critical vulnerability allows remote, unauthenticated attackers to execute arbitrary code on affected systems without user interaction. However, systems using the default MaxRequestBytes registry value in the Windows HTTP stack are not affected. If needed, you can change this registry setting to protect systems while testing and deploying the patch. Microsoft's security bulletin includes instructions and a PowerShell script for this workaround.

🔸 DoS - HTTP.sys (CVE-2026-49160). The same exploit is used as for the previous RCE vulnerability.

It is also worth paying attention to vulnerabilities that Microsoft has flagged as having a publicly available exploit:

🔹 SFB - Windows BitLocker (CVE-2026-50507). A successful attacker could bypass the BitLocker Device Encryption feature on the system storage device. An attacker with physical access to the target could exploit this vulnerability to gain access to encrypted data. According to Tenable, this is the "Bitskrieg" vulnerability discovered by the researcher known as Chaotic Eclipse/Nightmare Eclipse.

🔹 SFB - Secure Boot (CVE-2026-48570). An attacker who successfully exploited this vulnerability could bypass Secure Boot. This vulnerability was reported by Alon Leviev (STORM), who is known for previous research related to BootKitty and BlackLotus.

Among the remaining vulnerabilities, the following are worth highlighting:

🔹 RCE - Windows Kernel (CVE-2026-45657). This vulnerability allows remote, unauthenticated attackers to run code with SYSTEM privileges without any user interaction. In other words, it could be used to spread automatically between systems. The issue is caused by how the Windows kernel processes TCP/IP traffic. Microsoft rated this as "Exploitation Less Likely", but security researchers and exploit developers are already analyzing the patch and trying to build an exploit. Test and deploy this patch as soon as possible.

🔹 EoP - Windows Collaborative Translation Framework (CTFMON) (CVE-2026-45586). This vulnerability affects a component used for voice and handwriting recognition. If exploited, an attacker could gain SYSTEM privileges. Microsoft rates this vulnerability as "Exploitation More Likely".

🔹 RCE - Windows Remote Desktop Client (CVE-2026-42909, CVE-2026-42913, CVE-2026-42985, CVE-2026-42992, CVE-2026-42993, CVE-2026-44799, CVE-2026-44801, CVE-2026-47289, CVE-2026-47653, CVE-2026-47654, CVE-2026-48563). Successful exploitation would require a victim to connect to an attacker-controlled server using an affected version of the Remote Desktop Client. This action could trigger a heap-based buffer overflow, resulting in remote code execution.

🔹 RCE - DHCP Client Service (CVE-2026-44815). This vulnerability allows remote, unauthenticated attackers to execute code on affected systems without user interaction. Because the DHCP client is widely enabled across Windows systems, this vulnerability presents a broad attack surface. Organizations should prioritize testing and deploying the patch for this vulnerability as soon as possible.

🗒 Full Vulristics report

About Elevation of Privilege - Microsoft Defender "RedSun" (CVE-2026-41091) vulnerability

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About Elevation of Privilege - Microsoft Defender RedSun (CVE-2026-41091) vulnerability

About Elevation of Privilege - Microsoft Defender "RedSun" (CVE-2026-41091) vulnerability. Microsoft Defender is a built-in security solution developed by Microsoft to protect the Windows operating system and user data from viruses, malware, and other cyber threats in real time. An improper link resolution vulnerability prior to file access ("link following", CWE-59) in Microsoft Defender, specifically within the Malware Protection Engine component, allows an authenticated local attacker to escalate privileges to SYSTEM level. As a result, an attacker could gain full control over the affected system, including unrestricted access to data, the ability to modify system settings, install software, manage user accounts, and disable security protections.

🛠 An exploit for the vulnerability was published on GitHub by security researcher Nightmare Eclipse on April 15, alongside exploits targeting other Windows component vulnerabilities. The account was later removed by GitHub administrators; however, this did not prevent the exploit code from spreading further.

⚙️ The security advisory and patches were released on May 19 outside Microsoft's regular Patch Tuesday schedule. Versions of Microsoft Malware Protection Engine from 1.1.26030.3008 through 1.1.26040.8 are affected. Systems with Microsoft Defender disabled are not vulnerable. By default, Microsoft Defender automatically updates Windows security components, antivirus definitions, and Microsoft Malware Protection Engine, so no additional user action is typically required. Malware Protection Engine is updated monthly or as new threats emerge, while antivirus definitions are updated several times per day. Update checks may run automatically anywhere from once to several times daily when an Internet connection is available. Manual update checks are also supported.

👾 According to Microsoft, the vulnerability is being exploited in the wild. The vulnerability was added to the CISA KEV catalog on May 20.

💡 Special attention should be paid to server and desktop Windows hosts where Microsoft Defender is not disabled, but Internet access is unavailable for regular updates.