Tag Archives: KEV

About Remote Code Execution - Microsoft SharePoint (CVE-2026-58644) vulnerability

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About Remote Code Execution - Microsoft SharePoint (CVE-2026-58644) vulnerability

About Remote Code Execution - Microsoft SharePoint (CVE-2026-58644) vulnerability. Information about this vulnerability was published on July 14 as part of the July Microsoft Patch Tuesday. The vulnerability in Microsoft SharePoint Server, caused by a deserialization flaw (CWE-502), allows an attacker with Site Owner privileges or higher to inject and remotely execute arbitrary code on the SharePoint server. This can result in full server compromise, including the exfiltration of corporate documents and data, their modification or deletion, compromise of credentials accessible to the server, and further lateral movement into the organization's internal infrastructure.

The authentication requirement, of course, makes exploitation of the vulnerability more difficult. However, an attacker could potentially leverage the previously disclosed EoP vulnerability CVE-2026-56164. At the same time, there is currently no confirmation that these vulnerabilities have been exploited together as part of a single attack chain.

👾 Microsoft experts flagged this vulnerability as being exploited in the wild on the day of Patch Tuesday. Two days later, on July 16, the vulnerability was added to the CISA KEV catalog. Details of the attacks are not yet known.

🛠 No public exploits have been observed so far.

⚙️ Updates are available for Microsoft SharePoint Server 2016, 2019, and Subscription Edition.

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 "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

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.

May Linux Patch Wednesday

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May Linux Patch Wednesday

May Linux Patch Wednesday. A total of 1,638 vulnerabilities (474 in the Linux kernel). For comparison, in April there were 1,035 vulnerabilities (a record!). And this time it turns out to be a record again, more than one and a half times higher! The acceleration is both impressive and alarming. But we will see what happens next. At some point it should stabilize. Although the number of critical vulnerabilities is already so high that reviewing all of them becomes quite problematic. For 7 vulnerabilities there are signs of exploitation in the wild. And for another 264 there are public exploits. Let’s start, as usual, with vulnerabilities being actively exploited according to CISA KEV and VulnCheck KEV data. Here, at the top, as expected, are two high-profile ways to get a root shell:

🔻 EoP - Linux Kernel "Copy Fail" (CVE-2026-31431)
🔻 EoP - Linux Kernel "Dirty Frag" (CVE-2026-43500)

Other vulnerabilities being exploited in the wild:

🔻 RCE - Apache ActiveMQ (CVE-2026-40466). Based on the description, this appears to be a bypass of the fix for CVE-2026-34197, which I already wrote about earlier.

🔻 AuthBypass - Rclone (CVE-2026-41176). Rclone ("rsync for cloud storage") is a command-line utility for synchronizing files and directories between various cloud storage services and local systems. Exploitation of the vulnerability can lead to unauthorized access to sensitive administrative functionality, including configuration and operational RC methods.

🔻 RCE - NGINX (CVE-2026-42945). The bug enables unauthenticated remote code execution against servers using rewrite and set directives.

🔻 DoS - PgBouncer (CVE-2026-6664). PgBouncer is a lightweight, open-source connection pooler for PostgreSQL databases. It reduces connection overhead by managing a pool of connections to one or more PostgreSQL servers, improving performance and resource efficiency for applications with frequent short-lived database connections. An integer overflow in the network packet parsing code in PgBouncer before 1.25.2 bypasses a boundary check and can lead to a crash.

🔻 XSS - Postorius (CVE-2026-44742). The Postorius Django app provides a web user interface to access GNU Mailman. Mailman is free software for managing electronic mail discussion and e-newsletter lists. The vulnerability is being exploited according to VulnCheck KEV; however, no public exploits has been observed yet.

From the remaining vulnerabilities with public exploits, but without any signs of exploitation in the wild so far, the following can be highlighted:

🔸 RCE - Apache HTTP Server (CVE-2026-23918). Double-free error in Apache httpd mod_http2 stream cleanup, leading to pre-auth RCE.

🔸 RCE - Apache Tomcat (CVE-2026-34486). Apache Tomcat Tribes cluster communication module fails to discard messages when EncryptInterceptor decryption fails, allowing unauthenticated attackers to trigger Remote Code Execution via Java deserialization on port 4000.

🔸 RCE - ProFTPD (CVE-2026-42167). The flaw exists in how mod_sql handles certain logging variables (like %U), allowing an unauthenticated attacker to inject SQL commands via the USER command.

🔸 EoP - Linux Kernel "DirtyDecrypt" (CVE-2026-31635). Linux local privilege escalation in the RxRPC/GSSAPI decryption path. A missing skb_cow_data() check in rxgk_decrypt_skb() allows an unprivileged local attacker to corrupt cache pages and overwrite in-memory contents of read-only files.

🔸 EoP - Linux Kernel "Fragnesia" (CVE-2026-46300). I also analyzed this vulnerability earlier. A bug in skb_try_coalesce() allowing page-cache write via fragmented ESP packets.

🔸 EoP - Linux Kernel (CVE-2026-46333). Local root privilege escalation and credential disclosure in the Linux kernel ptrace path, discovered by researchers at Qualys.

🔸 EoP - PackageKit "Pack2TheRoot" (CVE-2026-41651). PackageKit is a free and open-source suite of software applications designed to provide a consistent and high-level abstraction layer for a number of different package management systems. The vulnerability allows an attacker to escalate privileges, potentially gaining root access or compromising the system.

🔸 ComInj - Composer (CVE-2026-40261, CVE-2026-40176). Composer is a dependency manager for PHP. The vulnerability exists in the Perforce::generateP4Command() method. Due to insufficient sanitization of repository configuration parameters (such as url, p4user, or client) when constructing shell commands, an attacker who controls a composer.json file can execute arbitrary commands on the victim's system when composer install or composer update is executed.

🗒 Full Vulristics report

May "In the Trend of VM" (#27): high-profile vulnerabilities in Linux, ActiveMQ, SharePoint, and Adobe Acrobat Reader

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May In the Trend of VM (#27): high-profile vulnerabilities in Linux, ActiveMQ, SharePoint, and Adobe Acrobat Reader

May "In the Trend of VM" (#27): high-profile vulnerabilities in Linux, ActiveMQ, SharePoint, and Adobe Acrobat Reader. Presenting the traditional monthly roundup of trending vulnerabilities according to Positive Technologies. While the previous April edition featured only one vulnerability, this one includes four, covering different technologies and attack scenarios.

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

🔻 EoP - Linux Kernel "Copy Fail" (CVE-2026-31431). The vulnerability allows an attacker to gain root privileges.

🔻 RCE - Apache ActiveMQ (CVE-2026-34197). A vulnerability in a solution widely used in enterprise systems and integration platforms.

🔻 Spoofing - Microsoft SharePoint Server (CVE-2026-32201). A vulnerability in a Microsoft solution widely used in enterprise systems for collaboration, document management, and internal portal development.

🔻 RCE - Adobe Reader (CVE-2026-34621). A vulnerability in a widely used PDF document viewer; actively exploited in phishing attacks.

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