June Patch Tuesday Breakdown: Critical Zero-Days, Legacy Risks & Urgent Security Fixes

Every month, Microsoft’s Patch Tuesday looms as a critical date on the IT administrator’s calendar, and this cycle is no exception: Microsoft has sounded the alarm on 66 vulnerabilities, with two already confirmed under active exploitation. While regular patching is routine, what makes this update particularly urgent is the breadth and severity of several flaws—including the targeting of long-outdated platforms and components many considered dead, such as Internet Explorer. This roundup will examine the June patch releases, dissect the technical and security implications, and address key considerations that Windows system operators, cybersecurity teams, and business leaders should understand now.

The Scale and Urgency of This Month’s Patch Bundle​

Microsoft’s latest release patches 66 security flaws, tagged in varying degrees of severity from “important” to “critical.” Ten of these vulnerabilities rate as critical, meaning remote attackers could easily seize control of affected systems. Significantly, two vulnerabilities—CVE-2025-33053 and CVE-2025-5419—are already being actively exploited in the wild, underscoring the real and present danger facing unpatched systems.
But perhaps the bigger warning flag is Microsoft’s decision to issue patches for CVE-2025-33053 on end-of-life platforms, including Windows Server 2008 and even Internet Explorer’s components, which has been officially unsupported for three years. This move is rare; Microsoft only patches obsolete products in exceptional circumstances, typically when a vulnerability presents such sweeping risk that it could facilitate large-scale, targeted attacks or wormable exploits.

Key Technical Takeaways​

• 66 vulnerabilities fixed, including ten critical-rated flaws
• Two actively exploited zero-days: CVE-2025-33053 (WebDAV) and CVE-2025-5419 (Chromium V8 in Microsoft Edge)
• Legacy patching: Microsoft has extended support for some legacy systems for one critical bug
• Numerous vulnerabilities in Office, SharePoint, Power Automate, Windows Netlogon, Remote Desktop Gateway, KDC Proxy Service, and core Windows components

Let’s break down the individual critical vulnerabilities and why they matter.

CVE-2025-33053: The WebDAV “One-Click” RCE Exploited by Stealth Falcon​

The standout flaw this month is CVE-2025-33053, a remote code execution vulnerability in the Web Distributed Authoring and Versioning (WebDAV) service. Affected for over a decade, WebDAV is embedded deeply into Windows’ remote file sharing and collaboration infrastructure. Exploitation requires only a single user click—a classic “one-click” attack.

Anatomy of the Exploit​

• Attack vector: The attacker sends a URL file disguised as a PDF, typically via a targeted spear-phishing campaign. When clicked, it triggers remote code execution on the victim’s system.
• Victims so far: At least one Turkish defense contractor, with evidence of broader targeted espionage campaigns.
• Attacker: Stealth Falcon, a group notorious for targeting the Middle East with customized zero-days, operational since at least 2012.
• Malware payload: Data exfiltration tools, including a custom keylogger

Check Point researchers, who discovered the exploit in the wild, emphasize that the delivery was highly targeted. The fake PDF attachments were meticulously named to maximize social engineering effectiveness. The implication: These are not opportunistic attacks but focused, likely state-sponsored campaigns.

Why the Patch is Unusual​

Most notably, Microsoft pushed patches for systems considered dead and out-of-support, namely Internet Explorer (retired in 2022) and Windows Server 2008. This is reminiscent of the out-of-band patches for EternalBlue in 2017, which foretold the WannaCry ransomware epidemic. The lesson should be unmistakable for IT operations teams: unpatched legacy Windows endpoints remain prevalent—and dangerous.

Attack Trends: Highly Targeted but Easily Generalizable​

While spear-phishing remains the delivery mechanism, the technical vulnerability is generic—opening itself to broader exploitation if attackers begin recycling the exploit for less sophisticated, mass-phishing campaigns. Systems exposed to the internet, configured with legacy WebDAV access, or retaining unused Internet Explorer code, are at heightened risk.

CVE-2025-5419: Memory Corruption in Chromium V8 Powers More Attacks​

The second major zero-day, CVE-2025-5419, is a memory corruption flaw in Chromium’s V8 JavaScript engine—a core element in not just Google Chrome, but also Microsoft Edge and other Chromium-based browsers. Google patched the flaw last week; Microsoft quickly bundled the fix in this Patch Tuesday drop.

Attack Details​

• Potential impact: Remote code execution through malicious web content or browser extensions
• Targeted component: Browser engine also used in popular Electron-based applications
• Attack surface: Broad—any unpatched browser or Electron app can be vulnerable

Historically, V8 vulnerabilities have formed the backbone of numerous high-profile browser exploits, including sandbox escapes and drive-by malware attacks. The urgency is escalated by the rapid weaponization of vulnerabilities in this class; attackers often exploit them within days or even hours post-disclosure.

Privilege Escalation, Office Exploits, and “Preview Pane” Dangers​

CVE-2025-33073: Elevation of Privilege in Windows SMB​

Another critical item is CVE-2025-33073, an elevation-of-privilege vulnerability in the Windows SMB client (Server Message Block), which has been publicly disclosed along with proof-of-concept exploit code. Although not yet observed being exploited in the wild, public exploit availability sharply raises the risk profile for enterprises.

• Exploit scenario: Attacker lures a user to access a malicious SMB server, then pivots to SYSTEM-level access
• CVSS score: 8.8 (High)
• Mitigation: Patch immediately and consider disabling SMBv1+ where feasible

Office: Four Critical Flaws, Preview Pane Exploits​

• CVE-2025-47162 (heap-based buffer overflow)
• CVE-2025-47164 (use-after-free)
• CVE-2025-47167 (type confusion)
• CVE-2025-47953 (use-after-free, less likely to be exploited)

All four critical Office vulnerabilities carry significant risk, particularly as they can be triggered via the document Preview Pane—meaning an attacker doesn’t even need the victim to open a file, just preview it. Insider attacks or phishing campaigns distributing weaponized Office files represent the most likely attack method.
Microsoft notes that for those on Microsoft 365, some patches may take additional time to roll out depending on update and release channels—a notable delay window for those reliant on fast-tracked defense.

SharePoint, Schannel, Remote Desktop, Kerberos​

Among the other standout criticals:

• SharePoint (CVE-2025-47172): Authenticated attacker can execute code remotely. Enterprise collaboration systems are frequent ransomware footholds.
• Windows Schannel (CVE-2025-29828): Fixes a memory leakage vulnerability in Windows’ core cryptographic stack.
• Remote Desktop Gateway (CVE-2025-32710): Allows for unauthorized access, an attractive vector for lateral movement in breach scenarios.
• KDC Proxy Service (CVE-2025-33071): Cryptographic protocol flaw, impacts Kerberos-based authentication.

These vulnerabilities affect core components integral to secure network operations and authentication. Their compromise may result in extensive lateral movement, credential theft, or man-in-the-middle attacks in enterprise environments.

Power Automate and Netlogon: High CVSS, Complex Exploitation​

• Power Automate (CVE-2025-47966): CVSS 9.8, rated highly likely to be weaponized. Patched out-of-cycle earlier this month.
• Windows Netlogon (CVE-2025-33070): “Complex” to exploit per Microsoft, but allows privilege escalation if successful. Even low-probability exploits warrant patching due to Netlogon’s role in Active Directory security.

Important Updates: Office, Storage, and Infrastructure​

Beyond the attention-getting criticals, the June update brings numerous “important” class patches, including for Office desktop/mobile, the Storage Management Provider, and networking services—each a potential stepping-stone for attack chains combining elevation, code execution, or information disclosure.

Third-Party Coordination: Adobe, Fortinet, SAP​

Microsoft’s Patch Tuesday cycle is mirrored by other software giants, accelerating the patch treadmill for IT security operations.

Adobe: Priority-One Fixes for Commerce, Acrobat, InDesign​

• Adobe Commerce (and Magento Open Source): Immediate fixes required for vulnerabilities in versions 2.4.8 and below—including B2B variants. Fortunately, no active exploits have been seen yet, but the e-commerce risk is high due to the sensitive customer data at stake.
• Adobe Experience Manager: Patches an eye-popping 254 CVEs in a single release, although most are XSS-related and rated “important.” Two critical fixes address potential arbitrary code execution issues.
• Adobe Acrobat: Ten patches, four critical—three of which address use-after-free memory flaws affecting both Windows and macOS.
• InDesign: Nine vulnerabilities, five critical, all of which could result in code execution if exploited.
• InCopy and Substance 3D: Critical out-of-bounds flaws corrected.

Adobe’s ongoing focus on cross-platform vulnerabilities highlights increasingly converged attack surfaces as cloud and desktop applications share significant codebases.

Fortinet: FortiAnalyzer and FortiManager on Alert Again​

Fortinet, frequent Patch Tuesday participants due to the popularity of their network appliances, this month addresses CVE-2023-42788 in FortiAnalyzer Cloud—an issue originally identified by researchers at Orange S.A. This is another reminder that perimeter devices remain in the crosshairs of sophisticated attackers, and older vulnerabilities sometimes linger for years before exploitation is uncovered and mitigated.

SAP: 14 Issues, NetWeaver Patch Tops Priority​

SAP’s June fixes address 14 security bugs. Only one, CVE-2025-42989 (NetWeaver Application Server), ranks as critical—with a high 9.6 CVSS score. The majority relate to missing authorization checks in the S/4HANA platform, which, if left unfixed, could result in unauthorized access or privilege escalation in business-critical ERP environments.

Security Community Perspective: The Implications of “Critical” Status​

When Microsoft and peers classify flaws as “critical,” it signifies not only technical severity but also a sense of immediacy: these bugs generally enable attackers to execute code remotely, escalate privileges, or subvert administrator controls with relative ease. The fact that two zero-days are under active exploitation, with highly targeted spear-phishing campaigns confirmed, makes this month’s drop far more urgent than the numerical volume of CVEs might otherwise suggest.

Industry Response and Patch Management Challenges​

• Legacy and “zombie” endpoints: Many organizations still operate end-of-life Windows systems, inadvertently sustaining attack surfaces believed retired. This month’s patches serve as a wake-up call to audit and decommission (or at minimum, tightly isolate) systems no longer under mainstream support.
• Spear phishing escalation: The Stealth Falcon attacks show remarkable targeting and operational security; however, once technical details of new vulnerabilities become public through patch advisories and reverse engineering, criminal actors inevitably adapt the tactics for more automated, mass-market campaigns.
• Browser and Office exploits: As remote and hybrid work proliferates, employees spend more time in browser and productivity apps—making “client-side” exploits particularly attractive to attackers. Companies must ensure automated patching for browsers and Office suites is enabled, whether on-premises or via cloud-managed endpoints.
• Integrated supply-chain risk: With third-party software (especially Adobe and SAP) now often installed alongside or embedded within Windows environments, coordinated patch cycles mean organizations must schedule, test, and—crucially—validate updates well beyond just Microsoft-branded software.

Best Practices for Patch Tuesday Response​

1. Audit Inventory and Patch Coverage​

Map all Windows endpoints, including servers, legacy devices, and virtualized instances. Ensure automated patching is enabled wherever possible, but do not assume success; manual validation reports and vulnerability scanning should be routine for high-priority systems.

2. Prioritize by Exploitability, Not Just CVSS​

Focus first on flaws with known exploits or public proof-of-concept code (CVE-2025-33053, CVE-2025-5419, CVE-2025-33073). Next, patch critical services and internet-facing components: browser engines, SMB/Netlogon, Office suite, Remote Desktop, and SharePoint.

3. Review Exposure to Legacy Components​

Isolate or deprecate systems reliant on Internet Explorer, WebDAV, or SMBv1. Consider additional segmentation or firewall controls until a patch can be verified.

4. Validate Patch Success and Monitor for New Exploits​

Real-world attacks often spike after a Patch Tuesday, as threat actors reverse-engineer updates to generate new attack methods for lagging organizations. Monitor security feeds and SIEM alerts for evidence of related intrusion attempts. Where feasible, consider deploying detection rules for indicators of compromise provided by Microsoft, Check Point, and other security firms.

5. Train End-Users—Again​

Targeted phishing remains the number one initial attack vector for exploitation. Frontline employees—including finance, legal, HR, and executives—should receive a rapid refresher about the dangers of email attachments, disguised URLs, and the importance of reporting suspicious content immediately.

Analysis: What Sets This Patch Drop Apart​

Strengths​

• Rapid Patch Turnaround: The short interval between Google’s Chromium V8 fix and Microsoft’s inclusion in Patch Tuesday demonstrates improved coordination across major vendors.
• Transparency: Microsoft’s expanding tradition of publicly disclosing actively exploited bugs and the circumstances of their discovery aids defenders, even as it may inform adversaries.
• Legacy Patch Release: Issuing fixes for unsupported endpoints underlines a broader “security-first” approach—though it’s also an indictment of the industry’s persistent dependency on obsolete code.

Weaknesses and Risks​

• Patch Fatigue and Testing Gaps: The volume and diversity of components affected—ranging from core OS to browser and third-party apps—strain IT teams, risking delayed deployments and possible downtime due to unforeseen compatibility issues.
• Lagging Cloud/365 Channels: Microsoft 365 users may wait several days for the most recent patches, leaving a short (but real) risk window.
• Lurking Legacy Systems: The need to patch defunct platforms like Internet Explorer highlights the ongoing reality that critical infrastructure and vertical industries (healthcare, utility, defense) have not migrated away from dangerous dependencies.
• Weaponization Timeline: With targeted zero-days already observed, broad criminal exploitation is only a matter of time. Automation and increasingly sophisticated phishing will likely follow.

Final Thoughts and Call to Action​

This Patch Tuesday’s bundle should not be viewed as routine maintenance. With multiple confirmed zero-days in the wild, a high number of critical vulnerabilities, and the rare step of patching products long declared dead, the message to organizations is clear: patch now, validate thoroughly, and continuously train staff on evolving phishing threats. The convergence of vulnerabilities across Microsoft, Adobe, SAP, and Fortinet platforms illustrates the interconnected risk of modern digital workspaces and the relentless pace of attacker innovation.
As IT environments grow in complexity, sustaining robust patch management is no longer merely technical hygiene—it is a frontline defense against corporate espionage, ransomware, and operational failure. For those who delay, the cost—and the exposure—will only rise, as attackers pivot rapidly from targeted campaigns to broad, automated exploitation. Administrators, take heed: the window to act closes rapidly after each Patch Tuesday.

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Source: theregister.com Microsoft warns of 66 flaws to fix for this Patch Tuesday