Exploits and vulnerabilities in Q2 2026

Summary

The Q2 2026 vulnerability report indicates a significant increase in registered CVEs, largely attributed to the widespread adoption of AI in both software development and vulnerability research. This trend has led to the emergence of new vulnerability classes, particularly in Linux networking, and a rise in the early publication of exploits for unpatched vulnerabilities. The report also notes the growing vulnerability landscape within open-source AI agents and frameworks.

Full text

Table of Contents Statistics on registered vulnerabilitiesExploitation statisticsWindows and Linux vulnerability exploitationMost common published exploitsVulnerability exploitation in APT attacksC2 frameworksLLM/AI tool vulnerabilitiesNotable vulnerabilitiesCVE-2026-25253: a gatewayUrl vulnerability in OpenClawCVE-2026-41948: a path traversal vulnerability in the Dify AI platformCVE-2026-45386: an improper access control vulnerability in Open WebUICVE-2026-45501: a vulnerability in Microsoft ExchangeConclusion and advice Authors Alexander Kolesnikov The vulnerability landscape shifted significantly in Q2 2026. First, the number of registered CVEs reached an unprecedented level. This is driven primarily by the widespread adoption of AI, both for application development and search for security flaws. This resulted in entire new classes of vulnerabilities emerging, particularly in the Linux networking subsystem. Second, security researchers have been publishing exploits for unpatched vulnerabilities more frequently. Publications like these can generate significant fallout, since they potentially open the door for attackers to target unprotected systems. Statistics on registered vulnerabilities This section provides statistical data on registered vulnerabilities. The data comes from Kaspersky’s vulnerability knowledge base, which draws on the CVE database as well as the Russian BDU database and GitHub Advisory (GHSA). As a result, the figures for previous reporting periods may differ from those published in earlier reports. We examine the number of registered vulnerabilities for each month over the last five years. As the chart below shows, this number continues to surge, a trend reflected across all the databases we track. It’s driven primarily by the widespread adoption of AI tools: as we predicted in our previous report, these tools have played a major role in the discovery of vulnerabilities in third-party software. Meanwhile, these tools often contain security issues of their own. For example, OpenClaw, a popular AI project, ranked 12th among those with the highest number of vulnerabilities discovered and published in Q2, with over 200 CVEs registered during the reporting period. Finally, AI development tools are also contributing to the vulnerability landscape, since the quality of the code they produce can vary widely. Therefore, the rate at which new vulnerabilities are discovered will inevitably keep growing. Total published vulnerabilities per month from 2022 through 2026 (download) Next, we analyze the number of new critical vulnerabilities (CVSS > 9.0) over the same period. Total critical vulnerabilities published per month from 2022 through 2026 (download) As the chart shows, the number of published critical vulnerabilities jumped sharply in Q2. This is because using AI for vulnerability research makes it possible to analyze massive amounts of previously unexamined code, uncover new attack surfaces, and identify entire classes of vulnerabilities that have gone unnoticed for decades. In particular, AI was used to find a series of Dirty Frag vulnerabilities in the Linux kernel. Exploitation statistics This section presents statistics on vulnerability exploitation for Q2 2026. The data draws on open sources and our telemetry. Windows and Linux vulnerability exploitation Q2 2026 saw a new precedent in the publication of vulnerabilities in Windows components and exploits for these: researchers no longer waiting for CVE registration, let alone patches. A case in point: a researcher who goes by Nightmare Eclipse (also known as Chaotic Eclipse) published a list of new “named” vulnerabilities across various Windows subsystems. At the time the technical details were published, none of the vulnerabilities had been assigned a CVE identifier: BlueHammer: a local privilege escalation vulnerability in Windows Defender. During signature database updates, a time-of-check to time-of-use (TOCTOU) race condition occurs, allowing an attacker to substitute the directory where temporary update files are written. The researcher published a fully functional exploit for the vulnerability. RedSun: another logical vulnerability in Windows Defender with a working exploit. Suspicious and malicious files marked as “cloud” can be overwritten or restored to their original directory with elevated privileges. The exploit incorporates fragments of algorithms that make it possible to leverage various logical vulnerabilities in Windows, effectively combining a large number of popular exploitation techniques. YellowKey: a vulnerability that lets the user bypass BitLocker full-disk encryption and access system data through the Windows Recovery Environment (WinRE). A fully functional exploit was also published. GreenPlasma: a vulnerability that enables system object injection via the CTF loader for the Collaborative Translation Framework (CTFMON) service in Windows. The original publication included an exploit with limited functionality. RougePlanet: yet another Windows Defender vulnerability that, like BlueHammer, stems from a TOCTOU issue, this time in the engine responsible for real-time system scanning. The published exploit uses the vulnerability to overwrite the system file wermgr.exe with a malicious one. UnDefend: another vulnerability in the Windows Defender service. This time, the exploit causes a denial of service and blocks updates. Even though such cases remain isolated for now, we believe they’ll grow into a full-fledged trend. Early publication of exploits gives attackers an advantage over software developers, who are left with no time to fix the issues. Veteran vulnerabilities in Windows software also remain relevant. These are the ones our solutions most frequently detect exploits for: CVE-2018-0802: a remote code execution (RCE) vulnerability in the Equation Editor component CVE-2017-11882: another RCE vulnerability also affecting Equation Editor CVE-2017-0199: a vulnerability in Microsoft Office and WordPad that allows an attacker to gain control over the system CVE-2023-38831: a vulnerability in WinRAR that involves improper handling of objects within an archive CVE-2025-6218 (formerly ZDI-CAN-27198): another WinRAR vulnerability allowing the specification of relative paths to extract files into arbitrary directories, potentially leading to malicious command execution CVE-2025-8088: a vulnerability similar in exploitation method to CVE-2025-6218. The attackers used NTFS Streams to circumvent controls on the directory into which files are being unpacked The vulnerabilities listed here can be leveraged to gain initial access to a vulnerable system and for privilege escalation. This underscores the critical importance of timely software updates. That said, the number of Windows users who encountered exploits declined slightly in Q2, hitting an 18-month low. Dynamics of the number of Windows users encountering exploits, Q1 2025 – Q2 2026. The number of users who encountered exploits in Q1 2025 is taken as 100% (download) Linux also hit a rough patch in Q2 2026. Specifically, the period saw the disclosure of the Dirty Frag family of vulnerabilities, which lets an attacker reliably escalate privileges within the operating system. All the vulnerabilities published in Q2 2026 were, in one way or another, related to the Linux caching subsystem. Here are the ones being most actively exploited: CVE-2026-31431 (Copy Fail): a local privilege escalation vulnerability in the Linux kernel that lets an unprivileged user modify the page cache and gain root privileges. Especially dangerous for cloud and containerized environments CVE-2026-43284, CVE-2026-43500 (Dirty Frag): a family of vulnerabilities in the Linux networking subsystem (IPsec ESP and RxRPC) that lets a local user overwrite the page cache and escalate privileges to root CVE-2026-46300 (Fragnesia): a local privilege escalation vulnerability in the Linux kernel related to packet fragment handling and the page cache

Indicators of Compromise

• cve — CVE-2026-25253
• cve — CVE-2026-41948
• cve — CVE-2026-45386
• cve — CVE-2026-45501

Entities