PATCHES

Unless you're an admin or vulnerability manager – then you're totally screwed

Microsoft set a record with its June Patch Tuesday release, addressing 206 CVEs across its products and shipping fixes for them, with 38 deemed critical and the rest important. Three are listed as publicly known, but none (so far) have been exploited in the wild.

We have no idea how many of these June bugs were uncovered using AI tools. Unlike last month’s patching event, when Redmond disclosed its agentic bug-hunting system found 16 of the 137 vulnerabilities, there’s no word on any AI assists for new releases. 

Still, it’s safe to assume AI played a major role. As Tom Gallagher, VP of engineering at Microsoft Security Response Center, said about May's Patch Tuesday with a whopping 30 critical flaws: “We expect releases to continue trending larger for some time.”

June’s Patch Tuesday proved Gallagher correct, surpassing May in both overall volume and critical bugs.

“I’ve been counting CVEs on Patch Tuesday since 2017, and this is by far the largest monthly release in that time,” Zero Day Initiative’s bug hunter in chief Dustin Childs said in his review. 

“It is extraordinary that Microsoft can produce so many patches in a single month, but it does raise concerns,” he added, asking, as we did: How many were found via AI?

And: “How many patches were generated using AI to assist in coding or testing? What quality issues may exist in these patches? And likely most importantly, is this the new normal?”

Childs noted that May and April also saw mega releases.

“Should sysadmins adjust their processes for prioritization and patch deployment based on this new volume of updates? Unfortunately, Microsoft is not providing those answers right now,” he wrote, adding in this fun fact: “The current number of CVEs shipped by Microsoft this year exceeds the total number of CVEs shipped in all of 2018.”

Wowza. 

While it’s fun to watch from a purely speculative standpoint, as in: "Will Microsoft top 300 next month?", our thoughts and prayers are nonetheless with sysadmins and vulnerability management teams drowning in the AI-induced vulnpocalypse by now. 

None of the Patch Tuesday security holes are listed as under attack – at least not yet – but three are listed as publicly known. Let’s take a look at those first.

Three known vulnerabilities

CVE-2026-49160 is an HTTP.sys denial of service vulnerability that we wrote about earlier this month. Calif researcher Quang Luong discovered the attack with an assist from OpenAI's Codex agent, named it HTTP/2 Bomb, and said it exploits the HTTP/2 header compression algorithm by sending thousands of tiny messages to the server, forcing it to rapidly allocate memory and ultimately crash.

At the time, a Microsoft spokesperson told The Register that Redmond was “aware and actively investigating appropriate mitigations.” On Tuesday, the tech giant fixed the security issue by introducing a new MaxHeadersCount registry setting, which allows users to limit the number of headers included in HTTP/2 and HTTP/3 requests, and should prevent denial-of-service attacks.

CVE-2026-50507, a security feature bypass bug in Windows BitLocker, is the second CVE listed as publicly disclosed, and “exploitation more likely.” An attacker with physical access to the vulnerable system could bypass the BitLocker Device Encryption feature and gain access to the device's encrypted data, according to the advisory.

This flaw also seems to be a patch for one of the zero-days dropped in the ongoing war between Microsoft and a disgruntled bug hunter known as Nightmare Eclipse - likely the YellowKey vulnerability disclosed in May. Nightmare has published details about and in some cases, full proof-of-concept exploit code for six zero-days, and promised a “bone shattering” release on June 14.

The third publicly known bug, CVE-2026-45586, is a Windows Collaborative Translation Framework (CTFMON) elevation of privilege vulnerability that can be abused by an authorized attacker to elevate privileges locally and gain SYSTEM access. From there, miscreants could deploy malware, steal data, and move laterally through the victim's environment - so patch this one sooner.

Plus these two (of 38) critical bugs

In addition to those three known vulnerabilities that made the rounds before Microsoft issued a patch, a couple of critical-rated 9.8 security flaws are worth highlighting this month.

The first, CVE-2026-45657, is a Windows kernel remote code execution (RCE) bug that allows remote, unauthenticated attackers to run code with system-level privileges without any user interaction. It’s due to an error in how the Windows kernel processes some TCP/IP data, and can be exploited by sending malicious network packets to a vulnerable Windows system, thus triggering the flaw. 

While it’s listed as “exploitation less likely” by Redmond, we like Childs’ response. “Rest assured that every researcher and bug shop on the planet is reversing this patch right now trying to create an exploit,” he said. “Test and deploy this patch quickly.”

CVE-2026-47291, an HTTP.sys RCE vulnerability that also earned a 9.8 CVSS rating, deserves attention as it can also be triggered with zero user interaction and Microsoft says it’s “more likely” to be exploited.

“This vulnerability creates severe business risk because HTTP.sys is used by Windows services that process HTTP traffic,” Alex Vovk, CEO and co-founder of patch-management vendor Action1, told The Register. “A successful attack could lead to server takeover, malware deployment, data theft, service disruption, and lateral movement across the environment. Internet-facing systems are especially exposed.”

The good news: systems using the Windows HTTP stack’s default MaxRequestBytes registry value are not affected. In the advisory, Redmond provides detailed instructions on how to edit registry settings, which can buy admins some time (and security) while deploying the patch. ®