In its April batch of patches, Microsoft fixes 108 flaws, including 19 “critical” flaws, five 0-days, and four NSA-discovered critical Exchange flaws
Today is Microsoft's April 2021 Patch Tuesday, and with it comes five zero-day vulnerabilities and more Critical Microsoft Exchange vulnerabilities.
BleepingComputerLawrence Abrams
Context & Ripple Effects
Microsoft’s April release sits in a recurring Patch Tuesday pattern rather than an isolated Exchange event: the related coverage records a June batch with seven zero-days, six exploited in the wild, followed by later releases that continued to include critical and zero-day fixes. The immediate importance is the concentration of issues in a single update cycle, including Exchange flaws identified by the NSA.
Subsequent coverage shows Microsoft continuing to ship broad security batches, including three actively exploited zero-days in its February 2023 release. That cadence makes patch prioritization a continuing operational requirement for Microsoft customers, not a one-off response.
First-order effects
Microsoft customers using Exchange must assess and deploy the April fixes alongside patches for the other disclosed critical and zero-day vulnerabilities.
Microsoft closes 108 reported flaws in one cycle, while the NSA-discovered Exchange issues put particular attention on organizations operating that product.
Second-order effects
Security and IT teams must triage Microsoft updates by exposure to Exchange and the five zero-days, competing with normal change-management windows and testing capacity.
The June release’s larger set of zero-days, many already exploited, reinforces that customers cannot treat a completed April deployment as the end of their near-term patch workload.
Third-order effects
Repeated Patch Tuesday releases containing critical and zero-day fixes are pushing Microsoft-dependent organizations toward continuous vulnerability prioritization rather than periodic, low-urgency update cycles.
If this release pattern persists, Exchange exposure and patch-deployment speed become enduring factors in how enterprises manage Microsoft platform risk.
The trend: Microsoft’s recurring critical and zero-day patch releases are making rapid, exposure-based vulnerability management a standing enterprise operation.
NSA urges applying critical Microsoft patches released today, as exploitation of these #vulnerabilities could allow persistent access and control of enterprise networks. https://msrc-blog.microsoft.com/ ...
DNSA Anne Neuberger comments on today's Microsoft Exchange Server patch release, which was spurred by vulnerabilities identified about the NSA: “'The U.S. Government will lead by example - we are requiring all agencies to immediately patch their Exchange servers” https://twitter.…
Happy Patch Tuesday! Time to get patching your Exchange Servers! Some critical vulns this month, with discovery credited to @NSACyber. Looks like a good example of coordinated vuln disclosure. I'd expect @CISAgov guidance for Federal agencies soon. https://techcommunity.microsoft…
❗ @CISAgov strongly urges organizations apply Microsoft's April Security Update to mitigate against newly disclosed significant vulnerabilities affecting Exchange Servers. See https://us-cert.gov/... for details & new ED 21-02 Supplemental Direction. #Cybersecurity #InfoSec #IT h…
Patch ASAP time again peeps! “...four more Critical remote code execution vulnerabilities discovered by the NSA were fixed in Microsoft Exchange today. Two of these vulnerabilities are pre-authentication, which means they do not require attackers to log in to the server first.” h…
hold on to your butts. and patch all your publicly addressable windows machines, ASAP. seriously. don't put it off. go now. wake up the ops guys or sysadmins if need be. patch. patch now https://twitter.com/...
While analyzing the CVE-2021-1732 exploit used by the BITTER APT group, our researchers discovered another zero-day that is believed to be linked to the same group. Here's what we know 👇 https://securelist.com/...
Microsoft is crediting the NSA with warning it about new ways for hackers to take control of on-premise Exchange servers, which are not yet being seen in the wild. NSA and others urge rapid application of the patches released today. https://twitter.com/...