CVE-2026-124194 is the Outlook zero-day for which Microsoft says it’s aware of active exploitation.
The post Exploited Outlook Zero-Day Among 1,094 Flaws Patched by Microsoft appeared first on SecurityWeek.
Microsoft did another four-digit patch drop today, releasing updates to fix almost 1,100 security vulnerabilities in its Windows operating systems and supported software. This month’s Patch Tuesday addresses 63 critical flaws — including a zero-day in Microsoft Outlook — and comes amid important security updates from other software makers, including Adobe, Apple, Google and Mozilla.
Image: Shutterstock.com. Diorama by @zepp1969.
November’s patch release from Redmond tackles 1,093 vulnerabilities, fixing 63 “critical” flaws that can be exploited to seize control over a Windows system with little or no help from users. Nearly half of those critical bugs are remote code execution vulnerabilities. Overall, 535 of the flaws addressed this month allow an attacker to elevate their privileges on a vulnerable device.
This latest round of updates means Microsoft has shipped more than 5,100 security patches so far this year, a staggering number considering that a year ago Microsoft was averaging around 100 patches per month. Microsoft credits advances in artificial intelligence for helping to find (and fix) such a large volume of security bugs in recent months. Last month, Microsoft pushed more than 1,400 fixes.
According to Redmond, just one of the flaws is already seeing active exploitation: CVE-2026-124194, a spoofing bug in Outlook. The advisory for CVE-2026-124194 says it affects Microsoft 365 Apps for Enterprise and editions of Microsoft Office.
Several other major software makers pushed security updates this week to fix critical weaknesses in their products. Apple on Monday released out-of-cycle security updates to fix at least nine vulnerabilities in iOS/iPadOS, macOS, watchOS and visionOS. Among the weaknesses reportedly fixed in Apple’s release include an iMessage flaw that could let a remote attacker join a group chat and receive its messages; the updates also fix a separate iMessage flaw that could let someone added to a group access messages sent before they joined.
Lee Neely, an instructor at the SANS Institute, noted that Apple backported the fix to iOS 18.
“I take notice when Apple releases fixes to more than two versions,” Neely wrote in a SANS newsletter today. “You really need to get to version 27.2.1 of their OSes and push folks who are holding onto devices which cannot run the current version. The best plan often involves setting an upgrade date for old hardware. Run through all your Apple devices and make sure everything is up to date, don’t assume the fixes went out automatically.”
Google this week released Chrome version 157.0.8103.50, which resolves nine security holes, including CVE-2026-125350, the sixth zero-day vulnerability this year for Chrome (this bug also being patched in Chromium-based browsers like Edge). The latest Chrome version follows its November 3 release, which fixed 213 vulnerabilities. A new version of Mozilla Firefox out today (Firefox 160) resolves almost 100 CVEs, about half of them high severity.
Adobe today released patches for at least 110 vulnerabilities across a range of products, with nearly half of the flaws rated high severity. Adobe said there is no evidence any of the security holes it addressed this month are being actively exploited.
Chris Goettl, vice president of product management at Ivanti, said it’s easy for security teams at large enterprises to feel overwhelmed by the volume and criticality of patches from Microsoft lately. But he notes that while some 95,000 vulnerabilities have been assigned CVEs this year across all vendors, only 217 have so far this year been added to the Known Exploited Vulnerabilities (KEV) list maintained by the U.S. Cybersecurity and Infrastructure Security Agency (CISA).
“Roughly four in ten of this year’s exploited vulnerabilities sit in operating systems, endpoint software, browsers, and server platforms, which a continuous patch strategy can close quickly,” Goettl said.”The rest calls for exposure management alongside patching, especially the 44% that sit in edge devices and IT management or remote access tools, the internet-facing systems that hold privileged access. Teams that can quickly identify those assets, confirm exposure and act on confirmed exploitation can focus on the small slice of vulnerabilities attackers are actively using, while the rest stays on the normal patch cadence.”
Please don’t neglect to back up any important data if you haven’t recently; generally speaking, this is a task best accomplished before applying operating system updates. As ever, if you experience any issues applying this month’s bundle of love from Microsoft, please drop a comment about it in the space below.
Microsoft today pushed updates to fix at least 56 security flaws in its Windows operating systems and supported software. This final Patch Tuesday of 2025 tackles one zero-day bug that is already being exploited, as well as two publicly disclosed vulnerabilities.
Despite releasing a lower-than-normal number of security updates these past few months, Microsoft patched a whopping 1,129 vulnerabilities in 2025, an 11.9% increase from 2024. According to Satnam Narang at Tenable, this year marks the second consecutive year that Microsoft patched over one thousand vulnerabilities, and the third time it has done so since its inception.
The zero-day flaw patched today is CVE-2025-62221, a privilege escalation vulnerability affecting Windows 10 and later editions. The weakness resides in a component called the “Windows Cloud Files Mini Filter Driver” — a system driver that enables cloud applications to access file system functionalities.
“This is particularly concerning, as the mini filter is integral to services like OneDrive, Google Drive, and iCloud, and remains a core Windows component, even if none of those apps were installed,” said Adam Barnett, lead software engineer at Rapid7.
Only three of the flaws patched today earned Microsoft’s most-dire “critical” rating: Both CVE-2025-62554 and CVE-2025-62557 involve Microsoft Office, and both can exploited merely by viewing a booby-trapped email message in the Preview Pane. Another critical bug — CVE-2025-62562 — involves Microsoft Outlook, although Redmond says the Preview Pane is not an attack vector with this one.
But according to Microsoft, the vulnerabilities most likely to be exploited from this month’s patch batch are other (non-critical) privilege escalation bugs, including:
–CVE-2025-62458 — Win32k
–CVE-2025-62470 — Windows Common Log File System Driver
–CVE-2025-62472 — Windows Remote Access Connection Manager
–CVE-2025-59516 — Windows Storage VSP Driver
–CVE-2025-59517 — Windows Storage VSP Driver
Kev Breen, senior director of threat research at Immersive, said privilege escalation flaws are observed in almost every incident involving host compromises.
“We don’t know why Microsoft has marked these specifically as more likely, but the majority of these components have historically been exploited in the wild or have enough technical detail on previous CVEs that it would be easier for threat actors to weaponize these,” Breen said. “Either way, while not actively being exploited, these should be patched sooner rather than later.”
One of the more interesting vulnerabilities patched this month is CVE-2025-64671, a remote code execution flaw in the Github Copilot Plugin for Jetbrains AI-based coding assistant that is used by Microsoft and GitHub. Breen said this flaw would allow attackers to execute arbitrary code by tricking the large language model (LLM) into running commands that bypass the user’s “auto-approve” settings.
CVE-2025-64671 is part of a broader, more systemic security crisis that security researcher Ari Marzuk has branded IDEsaster (IDE stands for “integrated development environment”), which encompasses more than 30 separate vulnerabilities reported in nearly a dozen market-leading AI coding platforms, including Cursor, Windsurf, Gemini CLI, and Claude Code.
The other publicly-disclosed vulnerability patched today is CVE-2025-54100, a remote code execution bug in Windows Powershell on Windows Server 2008 and later that allows an unauthenticated attacker to run code in the security context of the user.
For anyone seeking a more granular breakdown of the security updates Microsoft pushed today, check out the roundup at the SANS Internet Storm Center. As always, please leave a note in the comments if you experience problems applying any of this month’s Windows patches.
Carrie Roberts // My current favorite exploit is creating malicious outlook rules as described here. The rule is configured to download an executable file with an EXE extension (.exe) when an […]
The post Malicious Outlook Rule without an EXE appeared first on Black Hills Information Security, Inc..
Carrie Roberts // Getting a shell using a malicious Outlook rule is an awesome tool during a pentest and great fun! Nick Landers had a great post including enough information to make […]
The post Malicious Outlook Rules in Action appeared first on Black Hills Information Security, Inc..
Carrie Roberts // There are various reasons why having a webDAV server comes in handy. The main reason I created one was to execute a malicious Outlook rule attack as […]
The post Deploying a WebDAV Server appeared first on Black Hills Information Security, Inc..
Beau Bullock // Full Disclosure: Black Hills Information Security believes in responsible disclosure of vulnerabilities. This vulnerability was reported to Microsoft on September 28th, 2016. As of the publication date of […]
The post Bypassing Two-Factor Authentication on OWA & Office365 Portals appeared first on Black Hills Information Security, Inc..
Login