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Microsoft today released updates to fix more than 100 security flaws in its Windows operating systems and other software. At least 13 of the bugs received Microsoft’s most-dire “critical” rating, meaning they could be abused by malware or malcontents to gain remote access to a Windows system with little or no help from users.
August’s patch batch from Redmond includes an update for CVE-2025-53786, a vulnerability that allows an attacker to pivot from a compromised Microsoft Exchange Server directly into an organization’s cloud environment, potentially gaining control over Exchange Online and other connected Microsoft Office 365 services. Microsoft first warned about this bug on Aug. 6, saying it affects Exchange Server 2016 and Exchange Server 2019, as well as its flagship Exchange Server Subscription Edition.
Ben McCarthy, lead cyber security engineer at Immersive, said a rough search reveals approximately 29,000 Exchange servers publicly facing on the internet that are vulnerable to this issue, with many of them likely to have even older vulnerabilities.
McCarthy said the fix for CVE-2025-53786 requires more than just installing a patch, such as following Microsoft’s manual instructions for creating a dedicated service to oversee and lock down the hybrid connection.
“In effect, this vulnerability turns a significant on-premise Exchange breach into a full-blown, difficult-to-detect cloud compromise with effectively living off the land techniques which are always harder to detect for defensive teams,” McCarthy said.
CVE-2025-53779 is a weakness in the Windows Kerberos authentication system that allows an unauthenticated attacker to gain domain administrator privileges. Microsoft credits the discovery of the flaw to Akamai researcher Yuval Gordon, who dubbed it “BadSuccessor” in a May 2025 blog post. The attack exploits a weakness in “delegated Managed Service Account” or dMSA — a feature that was introduced in Windows Server 2025.
Some of the critical flaws addressed this month with the highest severity (between 9.0 and 9.9 CVSS scores) include a remote code execution bug in the Windows GDI+ component that handles graphics rendering (CVE-2025-53766) and CVE-2025-50165, another graphics rendering weakness. Another critical patch involves CVE-2025-53733, a vulnerability in Microsoft Word that can be exploited without user interaction and triggered through the Preview Pane.
One final critical bug tackled this month deserves attention: CVE-2025-53778, a bug in Windows NTLM, a core function of how Windows systems handle network authentication. According to Microsoft, the flaw could allow an attacker with low-level network access and basic user privileges to exploit NTLM and elevate to SYSTEM-level access — the highest level of privilege in Windows. Microsoft rates the exploitation of this bug as “more likely,” although there is no evidence the vulnerability is being exploited at the moment.
Feel free to holler in the comments if you experience problems installing any of these updates. As ever, the SANS Internet Storm Center has its useful breakdown of the Microsoft patches indexed by severity and CVSS score, and AskWoody.com is keeping an eye out for Windows patches that may cause problems for enterprises and end users.
Windows 10 users out there likely have noticed by now that Microsoft really wants you to upgrade to Windows 11. The reason is that after the Patch Tuesday on October 14, 2025, Microsoft will stop shipping free security updates for Windows 10 computers. The trouble is, many PCs running Windows 10 do not meet the hardware specifications required to install Windows 11 (or they do, but just barely).
If the experience with Windows XP is any indicator, many of these older computers will wind up in landfills or else will be left running in an unpatched state. But if your Windows 10 PC doesn’t have the hardware chops to run Windows 11 and you’d still like to get some use out of it safely, consider installing a newbie-friendly version of Linux, like Linux Mint.
Like most modern Linux versions, Mint will run on anything with a 64-bit CPU that has at least 2GB of memory, although 4GB is recommended. In other words, it will run on almost any computer produced in the last decade.
There are many versions of Linux available, but Linux Mint is likely to be the most intuitive interface for regular Windows users, and it is largely configurable without any fuss at the text-only command-line prompt. Mint and other flavors of Linux come with LibreOffice, which is an open source suite of tools that includes applications similar to Microsoft Office, and it can open, edit and save documents as Microsoft Office files.
If you’d prefer to give Linux a test drive before installing it on a Windows PC, you can always just download it to a removable USB drive. From there, reboot the computer (with the removable drive plugged in) and select the option at startup to run the operating system from the external USB drive. If you don’t see an option for that after restarting, try restarting again and hitting the F8 button, which should open a list of bootable drives. Here’s a fairly thorough tutorial that walks through exactly how to do all this.
And if this is your first time trying out Linux, relax and have fun: The nice thing about a “live” version of Linux (as it’s called when the operating system is run from a removable drive such as a CD or a USB stick) is that none of your changes persist after a reboot. Even if you somehow manage to break something, a restart will return the system back to its original state.
If only Patch Tuesdays came around infrequently — like total solar eclipse rare — instead of just creeping up on us each month like The Man in the Moon. Although to be fair, it would be tough for Microsoft to eclipse the number of vulnerabilities fixed in this month’s patch batch — a record 147 flaws in Windows and related software.
Yes, you read that right. Microsoft today released updates to address 147 security holes in Windows, Office, Azure, .NET Framework, Visual Studio, SQL Server, DNS Server, Windows Defender, Bitlocker, and Windows Secure Boot.
“This is the largest release from Microsoft this year and the largest since at least 2017,” said Dustin Childs, from Trend Micro’s Zero Day Initiative (ZDI). “As far as I can tell, it’s the largest Patch Tuesday release from Microsoft of all time.”
Tempering the sheer volume of this month’s patches is the middling severity of many of the bugs. Only three of April’s vulnerabilities earned Microsoft’s most-dire “critical” rating, meaning they can be abused by malware or malcontents to take remote control over unpatched systems with no help from users.
Most of the flaws that Microsoft deems “more likely to be exploited” this month are marked as “important,” which usually involve bugs that require a bit more user interaction (social engineering) but which nevertheless can result in system security bypass, compromise, and the theft of critical assets.
Ben McCarthy, lead cyber security engineer at Immersive Labs called attention to CVE-2024-20670, an Outlook for Windows spoofing vulnerability described as being easy to exploit. It involves convincing a user to click on a malicious link in an email, which can then steal the user’s password hash and authenticate as the user in another Microsoft service.
Another interesting bug McCarthy pointed to is CVE-2024-29063, which involves hard-coded credentials in Azure’s search backend infrastructure that could be gleaned by taking advantage of Azure AI search.
“This along with many other AI attacks in recent news shows a potential new attack surface that we are just learning how to mitigate against,” McCarthy said. “Microsoft has updated their backend and notified any customers who have been affected by the credential leakage.”
CVE-2024-29988 is a weakness that allows attackers to bypass Windows SmartScreen, a technology Microsoft designed to provide additional protections for end users against phishing and malware attacks. Childs said one of ZDI’s researchers found this vulnerability being exploited in the wild, although Microsoft doesn’t currently list CVE-2024-29988 as being exploited.
“I would treat this as in the wild until Microsoft clarifies,” Childs said. “The bug itself acts much like CVE-2024-21412 – a [zero-day threat from February] that bypassed the Mark of the Web feature and allows malware to execute on a target system. Threat actors are sending exploits in a zipped file to evade EDR/NDR detection and then using this bug (and others) to bypass Mark of the Web.”
Update, 7:46 p.m. ET: A previous version of this story said there were no zero-day vulnerabilities fixed this month. BleepingComputer reports that Microsoft has since confirmed that there are actually two zero-days. One is the flaw Childs just mentioned (CVE-2024-21412), and the other is CVE-2024-26234, described as a “proxy driver spoofing” weakness.
Satnam Narang at Tenable notes that this month’s release includes fixes for two dozen flaws in Windows Secure Boot, the majority of which are considered “Exploitation Less Likely” according to Microsoft.
“However, the last time Microsoft patched a flaw in Windows Secure Boot in May 2023 had a notable impact as it was exploited in the wild and linked to the BlackLotus UEFI bootkit, which was sold on dark web forums for $5,000,” Narang said. “BlackLotus can bypass functionality called secure boot, which is designed to block malware from being able to load when booting up. While none of these Secure Boot vulnerabilities addressed this month were exploited in the wild, they serve as a reminder that flaws in Secure Boot persist, and we could see more malicious activity related to Secure Boot in the future.”
For links to individual security advisories indexed by severity, check out ZDI’s blog and the Patch Tuesday post from the SANS Internet Storm Center. Please consider backing up your data or your drive before updating, and drop a note in the comments here if you experience any issues applying these fixes.
Adobe today released nine patches tackling at least two dozen vulnerabilities in a range of software products, including Adobe After Effects, Photoshop, Commerce, InDesign, Experience Manager, Media Encoder, Bridge, Illustrator, and Adobe Animate.
KrebsOnSecurity needs to correct the record on a point mentioned at the end of March’s “Fat Patch Tuesday” post, which looked at new AI capabilities built into Adobe Acrobat that are turned on by default. Adobe has since clarified that its apps won’t use AI to auto-scan your documents, as the original language in its FAQ suggested.
“In practice, no document scanning or analysis occurs unless a user actively engages with the AI features by agreeing to the terms, opening a document, and selecting the AI Assistant or generative summary buttons for that specific document,” Adobe said earlier this month.
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