CVE-2026-45498

Rapid7 · Jun 09, 2026

Microsoft is publishing 200 vulnerabilities on June 2026 Patch Tuesday. Microsoft is not aware of exploitation in the wild for any of these vulnerabilities, and is aware of public disclosure for three. This is similar to last month’s Patch Tuesday, however several of last month’s vulnerabilities ended up on CISA KEV in the days following their publication. So far this month, Microsoft has provided patches to address 360 browser vulnerabilities, which is an order of magnitude more than has been typical in any given month over the past few years. As usual, browser vulns are not included in the Patch Tuesday count above. Indeed, the vast, and presumably sustained, uptick in the number of browser vulnerabilities has led to Microsoft no longer enumerating Chromium CVEs in the Security Update Guide. Other vulnerability categories, especially Linux kernel vulnerabilities, are seeing a similar increase in AI-assisted vulnerability reports.What's the opposite of coordinated disclosure?In recent weeks, an independent vulnerability researcher going by the pseudonym Nightmare Eclipse has attracted significant attention by publishing details of six Microsoft vulnerabilities, including elevation of privilege vulnerabilities in Defender, and a Secure Boot disk encryption bypass. The researcher provided full proof-of-concept code for some, and provided  significant-but-incomplete detail around the path to exploitation for others. Microsoft has confirmed that these disclosures were not coordinated, and it is clear that the relationship between this researcher and Microsoft is less than cordial. Two of the disclosures emerged in the hours after last month’s Patch Tuesday, which provides maximum visibility, while limiting Microsoft’s ability to respond without out-of-cycle patches.At time of writing, Microsoft has provided mitigation advice and patches for CVE-2026-33825, CVE-2026-45585, CVE-2026-45498, and CVE-2026-41091, leaving only two elevation of privilege vulnerabilities...