Tag Archives: exploit

July "In the Trend of VM" (#29): Microsoft Exchange Server vulnerability

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July In the Trend of VM (#29): Microsoft Exchange Server vulnerability

July "In the Trend of VM" (#29): Microsoft Exchange Server vulnerability. Here is my traditional monthly roundup of trending vulnerabilities, according to Positive Technologies. The previous June edition featured four vulnerabilities. This time, there's only one.

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

🔻 XSS - Microsoft Exchange (CVE-2026-42897). The vulnerability allows attackers to execute arbitrary JavaScript in a user's browser when the user opens a malicious email in Outlook Web Access (OWA). A public proof-of-concept exploit is available, and the vulnerability has already been exploited in the wild.

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

About Cross Site Scripting - Microsoft Exchange (CVE-2026-42897) vulnerability

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About Cross Site Scripting - Microsoft Exchange (CVE-2026-42897) vulnerability

About Cross Site Scripting - Microsoft Exchange (CVE-2026-42897) vulnerability. The vulnerability was fixed on May 14 outside the regular Microsoft Patch Tuesday cycle. Improper neutralization of input during web page generation (CWE-79, XSS) in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network. In practical terms, this means that a remote attacker could exploit this vulnerability by sending a specially crafted email to a user. If the user opens the email in Outlook Web Access and certain interaction conditions are met, arbitrary JavaScript can be executed in the browser context. As a result, the attacker may gain control of the user's mailbox by using an active user session.

👾 Microsoft experts immediately reported signs of active exploitation in the wild for this vulnerability. The vulnerability was added to the CISA KEV on May 15.

⚒️ A public exploit for the vulnerability was published on GitHub on May 15 as well.

⚙️ Initially, mitigation measures were recommended to address the vulnerability, delivered via the Exchange Emergency Mitigation (EM) service or by using the Exchange on-premises Mitigation Tool (EOMT) script. Security updates that fix the vulnerability in Microsoft Exchange Server Subscription Edition RTM, Exchange Server 2016, and Exchange Server 2019 were released almost a month later, on June 9. Microsoft experts recommended keeping the mitigations enabled even after applying the patch, as they provide an additional layer of protection. However, applying these mitigations may cause issues (for example, errors when printing calendars and displaying images in OWA).

⚠️ Please note that Exchange Server 2016 and 2019, which are out of support, are also affected by this vulnerability. Only customers enrolled in the Period 2 Extended Security Update (ESU) program are eligible to receive Exchange Server 2016 and 2019 security updates released between May and October 2026.

June Linux Patch Wednesday

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June Linux Patch Wednesday

June Linux Patch Wednesday. A total of 1,888 vulnerabilities (324 in the Linux kernel, and a whopping 728 in Chromium ❗️). For comparison, there were 1,638 vulnerabilities in May. The increase isn't as dramatic as it was from April to May, but it's still a new record. One of the vulnerabilities has been flagged as actively exploited in the wild:

🔻 RCE - Chromium (CVE-2026-11645). Chromium is the open-source web browser project that serves as the foundation for many modern browsers, including Google Chrome, Microsoft Edge, Brave, Opera, and Vivaldi. A publicly available Metasploit module exploits a vulnerability in the web browser's V8 JavaScript engine. The vulnerability is triggered by a specific code pattern that causes type confusion between internal V8 objects, resulting in out-of-bounds memory access. Successful exploitation may lead to remote code execution in the context of the browser process.

There are also 109 vulnerabilities with public exploits or evidence that exploits exist, although there are no signs of active exploitation in real-world attacks yet. Among them, the following stand out:

🔸 EoP - Linux Kernel "CIFSwitch" (CVE-2026-46243). This vulnerability could allow attackers to forge CIFS authentication key descriptions, abuse the kernel's key request mechanism, and gain root privileges.

🔸 EoP - Linux Kernel "PinTheft" (CVE-2026-43494). On a successfully exploited configuration, the chain completes and hands off to the discovered SUID binary with an overwritten first page - yielding a root shell if the race and kernel state align.

🔸 RCE - Apache ActiveMQ (CVE-2026-42588). ActiveMQ is an open-source message broker written in Java. Exploitation of this vulnerability requires valid credentials for the ActiveMQ Web Console. However, the default credentials are admin/admin.

🔸 InfDisc - Squid "Squidbleed" (CVE-2026-47729). Squid is an open-source caching proxy server. The vulnerability causes Squid's FTP parser to read beyond the boundary of a memory buffer, into a region that may contain a previous user's uncleared HTTP request data.

🔸 AuthBypass - Nextcloud (CVE-2026-45156). Nextcloud is an open source content collaboration platform. A missing signature verification in User OIDC allowed a malicious ID4me authority to identify as any user.

🔸 XSS - Nextcloud (CVE-2025-59788). A vulnerability in a reachable files_pdfviewer example directory in Nextcloud allows attackers to execute arbitrary JavaScript in the context of a user's browser via a crafted PDF file to viewer.html.

🔸 XSS - Roundcube (CVE-2026-48849). Roundcube is a free, open-source webmail application. An unsanitized subject field in the draft restored value could lead to stored XSS/HTML/CSS injection on shared mailboxes.

🔸 DoS - ImageMagick (CVE-2026-46522). ImageMagick is an open-source image processing tool used to create, edit, and convert images. Due to a missing check in the MIFF decoder, a crafted file could cause an infinite loop resulting in CPU exhaustion.

🗒 Full Vulristics report

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.

About Remote Code Execution - PAN-OS (CVE-2026-0300) vulnerability

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About Remote Code Execution - PAN-OS (CVE-2026-0300) vulnerability

About Remote Code Execution - PAN-OS (CVE-2026-0300) vulnerability. PAN-OS is an operating system for Palo Alto Networks firewalls and security platforms. User-ID™ Authentication Portal (also known as Captive Portal) is a non-default PAN-OS feature used to map IP addresses to usernames. By exploiting a buffer overflow vulnerability (CWE-787), an unauthenticated remote attacker can send specially crafted packets to a device with the Authentication Portal enabled, achieving arbitrary code execution with root privileges on the affected device. No authentication or user interaction is required. If the vulnerability is successfully exploited, the attacker gains full control over network traffic: they can intercept, modify, or block connections, access sensitive data, bypass security policies, hide traces of compromise, install backdoors, and use the device as a foothold for attacks on internal infrastructure.

⚙️ The vendor security advisory was published on May 6. PA-Series and VM-Series firewalls are affected. Prisma Access, Cloud NGFW, and Panorama appliances are not impacted by this vulnerability. Security updates for affected devices became available on May 13. As a workaround, the vendor recommended restricting User-ID™ Authentication Portal access to only trusted internal zones or disabling the User-ID™ Authentication Portal entirely if it is not required.

👾 On the same day, May 6, researchers from Palo Alto Networks Unit 42 published a report on active exploitation of the vulnerability in the wild. Post-exploitation activity includes deployment of publicly available tunneling tools (EarthWorm, ReverseSocks5), Active Directory enumeration using credentials likely obtained from the firewall, and systematic destruction of logs and other evidence of compromise. On the same day, the vulnerability was added to the CISA KEV catalog.

🛠 A public exploit was also published on GitHub on May 6.

🌐 PAN-OS is among the most widely deployed enterprise firewall operating systems in the world. As of June 5, Shodan identifies approximately 135,755 internet-facing PAN-OS instances, representing a significant attack surface.