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Microsoft today released updates to plug at least 121 security holes in its Windows operating systems and software, including one vulnerability that is already being exploited in the wild. Eleven of those flaws earned Microsoft’s most-dire “critical” rating, meaning malware or malcontents could exploit them with little to no interaction from Windows users.
The zero-day flaw already seeing exploitation is CVE-2025-29824, a local elevation of privilege bug in the Windows Common Log File System (CLFS) driver. Microsoft rates it as “important,” but as Chris Goettl from Ivanti points out, risk-based prioritization warrants treating it as critical.
This CLFS component of Windows is no stranger to Patch Tuesday: According to Tenable’s Satnam Narang, since 2022 Microsoft has patched 32 CLFS vulnerabilities — averaging 10 per year — with six of them exploited in the wild. The last CLFS zero-day was patched in December 2024.
Narang notes that while flaws allowing attackers to install arbitrary code are consistently top overall Patch Tuesday features, the data is reversed for zero-day exploitation.
“For the past two years, elevation of privilege flaws have led the pack and, so far in 2025, account for over half of all zero-days exploited,” Narang wrote.
Rapid7’s Adam Barnett warns that any Windows defenders responsible for an LDAP server — which means almost any organization with a non-trivial Microsoft footprint — should add patching for the critical flaw CVE-2025-26663 to their to-do list.
“With no privileges required, no need for user interaction, and code execution presumably in the context of the LDAP server itself, successful exploitation would be an attractive shortcut to any attacker,” Barnett said. “Anyone wondering if today is a re-run of December 2024 Patch Tuesday can take some small solace in the fact that the worst of the trio of LDAP critical RCEs published at the end of last year was likely easier to exploit than today’s example, since today’s CVE-2025-26663 requires that an attacker win a race condition. Despite that, Microsoft still expects that exploitation is more likely.”
Among the critical updates Microsoft patched this month are remote code execution flaws in Windows Remote Desktop services (RDP), including CVE-2025-26671, CVE-2025-27480 and CVE-2025-27482; only the latter two are rated “critical,” and Microsoft marked both of them as “Exploitation More Likely.”
Perhaps the most widespread vulnerabilities fixed this month were in web browsers. Google Chrome updated to fix 13 flaws this week, and Mozilla Firefox fixed eight bugs, with possibly more updates coming later this week for Microsoft Edge.
As it tends to do on Patch Tuesdays, Adobe has released 12 updates resolving 54 security holes across a range of products, including ColdFusion, Adobe Commerce, Experience Manager Forms, After Effects, Media Encoder, Bridge, Premiere Pro, Photoshop, Animate, AEM Screens, and FrameMaker.
Apple users may need to patch as well. On March 31, Apple released a huge security update (more than three gigabytes in size) to fix issues in a range of their products, including at least one zero-day flaw.
And in case you missed it, on March 31, 2025 Apple released a rather large batch of security updates for a wide range of their products, from macOS to the iOS operating systems on iPhones and iPads.
Earlier today, Microsoft included a note saying Windows 10 security updates weren’t available but would be released as soon as possible. It appears from browsing askwoody.com that this snafu has since been rectified. Either way, if you run into complications applying any of these updates please leave a note about it in the comments below, because the chances are good that someone else had the same problem.
As ever, please consider backing up your data and or devices prior to updating, which makes it far less complicated to undo a software update gone awry. For more granular details on today’s Patch Tuesday, check out the SANS Internet Storm Center’s roundup. Microsoft’s update guide for April 2025 is here.
For more details on Patch Tuesday, check out the write-ups from Action1 and Automox.
Microsoft today released updates to plug at least 70 security holes in Windows and Windows software, including one vulnerability that is already being exploited in active attacks.
The zero-day seeing exploitation involves CVE-2024-49138, a security weakness in the Windows Common Log File System (CLFS) driver — used by applications to write transaction logs — that could let an authenticated attacker gain “system” level privileges on a vulnerable Windows device.
The security firm Rapid7 notes there have been a series of zero-day elevation of privilege flaws in CLFS over the past few years.
“Ransomware authors who have abused previous CLFS vulnerabilities will be only too pleased to get their hands on a fresh one,” wrote Adam Barnett, lead software engineer at Rapid7. “Expect more CLFS zero-day vulnerabilities to emerge in the future, at least until Microsoft performs a full replacement of the aging CLFS codebase instead of offering spot fixes for specific flaws.”
Elevation of privilege vulnerabilities accounted for 29% of the 1,009 security bugs Microsoft has patched so far in 2024, according to a year-end tally by Tenable; nearly 40 percent of those bugs were weaknesses that could let attackers run malicious code on the vulnerable device.
Rob Reeves, principal security engineer at Immersive Labs, called special attention to CVE-2024-49112, a remote code execution flaw in the Lightweight Directory Access Protocol (LDAP) service on every version of Windows since Windows 7. CVE-2024-49112 has been assigned a CVSS (badness) score of 9.8 out of 10.
“LDAP is most commonly seen on servers that are Domain Controllers inside a Windows network and LDAP must be exposed to other servers and clients within an enterprise environment for the domain to function,” Reeves said. “Microsoft hasn’t released specific information about the vulnerability at present, but has indicated that the attack complexity is low and authentication is not required.”
Tyler Reguly at the security firm Fortra had a slightly different 2024 patch tally for Microsoft, at 1,088 vulnerabilities, which he said was surprisingly similar to the 1,063 vulnerabilities resolved in 2023 and the 1,119 vulnerabilities resolved in 2022.
“If nothing else, we can say that Microsoft is consistent,” Reguly said. “While it would be nice to see the number of vulnerabilities each year decreasing, at least consistency lets us know what to expect.”
If you’re a Windows end user and your system is not set up to automatically install updates, please take a minute this week to run Windows Update, preferably after backing up your system and/or important data.
System admins should keep an eye on AskWoody.com, which usually has the details if any of the Patch Tuesday fixes are causing problems. In the meantime, if you run into any problems applying this month’s fixes, please drop a note about in the comments below.
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