Microsoft Corp. today released software updates to plug at least 570 security holes in its Windows operating systems and other software, almost triple the number of vulnerabilities the software giant fixed in its record-smashing Patch Tuesday release last month. Microsoft attributed the burgeoning patch counts to vulnerability discoveries aided by artificial intelligence.

Nearly 60 of the bugs quashed in July’s Patch Tuesday earned a “critical” severity rating, meaning miscreants or malware could use them to seize remote control over a Windows device with little or no help from the user. Microsoft also addressed three zero-day flaws, including two that are already being exploited in the wild.

Two of the zero-day weaknesses allow an attacker to elevate their user rights on a Windows system, as do approximately 250 other elevation of privilege flaws fixed this month; they include CVE-2026-56155 — an Active Directory Federation Services bug — and CVE-2026-56164, a Microsoft Sharepoint vulnerability.

CVE-2026-50661 is a security feature bypass in Windows BitLocker that could allow attackers to gain access to encrypted data if they have physical access to the device. Microsoft said this bug has been detailed publicly, but that it is not aware of any active exploitation.

In a blog post on July 9, Microsoft Executive Vice President Pavan Davuluri wrote that Windows users will notice “a higher volume of security updates included in each security release” as a result of AI aiding in the discovery of vulnerabilities.

“The pace of vulnerability discovery is changing with advances in AI making it possible to find more issues, faster, across more code, with new mechanisms that can accelerate both discovery and analysis,” Davuluri wrote.

Jack Bicer, director of vulnerability research at Action1, called attention to CVE-2026-48561, a remote code execution flaw in Microsoft Copilot (with a 9.6 CVSS threat score) that allows an unauthorized attacker to execute code over the network. Microsoft says an attacker could exploit this bug by hosting a malicious website that causes Microsoft Edge for Android to automatically send crafted prompts to Copilot when a user visits the site.

As AI advances the state of vulnerability discovery and remediation, it is also making it easier for attackers to quickly devise working exploits for known software flaws. Microsoft has long labeled security bugs using its “exploitability index,” which is Redmond’s best guess as to how likely it is that attackers will be able to figure out a reliable way to exploit a given vulnerability.

But Satnam Narang, senior staff research engineer at Tenable, argues that Microsoft’s exploitability index needs to do a better job of shifting with the machine speed of discovery. For example, Microsoft originally gave this month’s SharePoint zero-day an exploitability rating of “less likely,” although the flaw was added to CISA’s Known Exploited Vulnerabilities list on July 1.

“Anthropic’s Red Team’s own findings for known vulnerabilities (n-days) revealed how fragile this system has become, with its Mythos Preview model being able to produce proof-of-concept exploits for 13 of 14 vulnerabilities that were rated ‘Exploitation Less Likely’ or ‘Exploitation Unlikely,'” Narang said. “What this means is that our way of looking at Patch Tuesday has changed, because the exploitability index is centered around humans, not AI tools, and as these tools continue to improve, defense needs to improve alongside it.”

Chris Goettl at Ivanti observed that the record patch numbers from Microsoft come as a number of other major software makers are increasing their patch cadence, including Adobe which announced today it is moving to twice-monthly security bulletins published on the 2nd and 4th Tuesday of each month (Adobe also cited AI for accelerating their patch cycles). Cisco, Mozilla and Oracle also are shipping updates more frequently, while Google’s patch batches in June 2026 totaled more than 900 security fixes, Goettl noted.

Backing up your Windows system and/or data is always a good idea before applying operating system updates. Given the volume of patches addressed this month it may be wise for end users to wait a few days before applying these fixes. It’s not uncommon for security patches to introduce system stability issues, and those chances probably increase quite a bit with the gigantic patch count released today.

Further reading:

Action1’s Patch Tuesday blog

Automox’s rundown

Microsoft today pushed software updates to fix a staggering 167 security vulnerabilities in its Windows operating systems and related software, including a SharePoint Server zero-day and a publicly disclosed weakness in Windows Defender dubbed “BlueHammer.” Separately, Google Chrome fixed its fourth zero-day of 2026, and an emergency update for Adobe Reader nixes an actively exploited flaw that can lead to remote code execution.

Redmond warns that attackers are already targeting CVE-2026-32201, a vulnerability in Microsoft SharePoint Server that allows attackers to spoof trusted content or interfaces over a network.

Mike Walters, president and co-founder of Action1, said CVE-2026-32201 can be used to deceive employees, partners, or customers by presenting falsified information within trusted SharePoint environments.

“This CVE can enable phishing attacks, unauthorized data manipulation, or social engineering campaigns that lead to further compromise,” Walters said. “The presence of active exploitation significantly increases organizational risk.”

Microsoft also addressed BlueHammer (CVE-2026-33825), a privilege escalation bug in Windows Defender. According to BleepingComputer, the researcher who discovered the flaw published exploit code for it after notifying Microsoft and growing exasperated with their response. Will Dormann, senior principal vulnerability analyst at Tharros, says he confirmed that the public BlueHammer exploit code no longer works after installing today’s patches.

Satnam Narang, senior staff research engineer at Tenable, said April marks the second-biggest Patch Tuesday ever for Microsoft. Narang also said there are indications that a zero-day flaw Adobe patched in an emergency update on April 11 — CVE-2026-34621 — has seen active exploitation since at least November 2025.

Adam Barnett, lead software engineer at Rapid7, called the patch total from Microsoft today “a new record in that category” because it includes nearly 60 browser vulnerabilities. Barnett said it might be tempting to imagine that this sudden spike was tied to the buzz around the announcement a week ago today of Project Glasswing — a much-hyped but still unreleased new AI capability from Anthropic that is reportedly quite good at finding bugs in a vast array of software.

But he notes that Microsoft Edge is based on the Chromium engine, and the Chromium maintainers acknowledge a wide range of researchers for the vulnerabilities which Microsoft republished last Friday.

“A safe conclusion is that this increase in volume is driven by ever-expanding AI capabilities,” Barnett said. “We should expect to see further increases in vulnerability reporting volume as the impact of AI models extend further, both in terms of capability and availability.”

Finally, no matter what browser you use to surf the web, it’s important to completely close out and restart the browser periodically. This is really easy to put off (especially if you have a bajillion tabs open at any time) but it’s the only way to ensure that any available updates get installed. For example, a Google Chrome update released earlier this month fixed 21 security holes, including the high-severity zero-day flaw CVE-2026-5281.

For a clickable, per-patch breakdown, check out the SANS Internet Storm Center Patch Tuesday roundup. Running into problems applying any of these updates? Leave a note about it in the comments below and there’s a decent chance someone here will pipe in with a solution.