Vulnerability database
Every flaw the U.S. government’s cybersecurity agency (CISA) has confirmed attackers are using, plus the new WordPress plugin and theme bugs published each day, sorted by what they mean for a small business. We refresh it twice a day. If you see something your website or office runs, tell us.
6 results
May 20, 2026Microsoft Defender Denial of Service VulnerabilityCVE-2026-45498 · Computers, phones & browsers · Microsoft · reported by secure@microsoft.comExploitedMedium 4
Microsoft Defender contains an unspecified vulnerability that allows for denial of service.
- Product
- Defender
- On CISA’s list since
- May 20, 2026 (federal fix deadline Jun 3, 2026)
- What to do
- Attackers are using this now. Install Microsoft’s update today. If there is no update for your version, take the product off the internet or stop using it until there is.
Full record and what to do →NVD recordCISA catalogmsrc.microsoft.comcisa.gov
May 20, 2026Microsoft Defender Link Following VulnerabilityCVE-2026-41091 · Computers, phones & browsers · Microsoft · reported by secure@microsoft.comExploitedHigh 7.8
Microsoft Defender contains a link following vulnerability that allows an authorized attacker to elevate privileges locally.
- Product
- Defender
- On CISA’s list since
- May 20, 2026 (federal fix deadline Jun 3, 2026)
- What to do
- Attackers are using this now. Install Microsoft’s update today. If there is no update for your version, take the product off the internet or stop using it until there is.
Full record and what to do →NVD recordCISA catalogmsrc.microsoft.comcisa.gov
Apr 22, 2026Microsoft Defender Insufficient Granularity of Access Control VulnerabilityCVE-2026-33825 · Computers, phones & browsers · Microsoft · reported by secure@microsoft.comExploitedRansomwareHigh 7.8
Microsoft Defender contains an insufficient granularity of access control vulnerability that could allow an authorized attacker to escalate privileges locally.
- Product
- Defender
- On CISA’s list since
- Apr 22, 2026 (federal fix deadline May 6, 2026)
- What to do
- Attackers are using this now. Install Microsoft’s update today (ransomware groups use this one). If there is no update for your version, take the product off the internet or stop using it until there is.
Full record and what to do →NVD recordCISA catalogmsrc.microsoft.comcisa.gov
Jul 11, 2023Microsoft Windows Defender SmartScreen Security Feature Bypass VulnerabilityCVE-2023-32049 · Computers, phones & browsers · Microsoft · reported by secure@microsoft.comExploitedHigh 8.8
Microsoft Windows Defender SmartScreen contains a security feature bypass vulnerability that allows an attacker to bypass the Open File - Security Warning prompt.
- Product
- Windows
- On CISA’s list since
- Jul 11, 2023 (federal fix deadline Aug 1, 2023)
- What to do
- Attackers are using this now. Install Microsoft’s update today. If there is no update for your version, take the product off the internet or stop using it until there is.
Full record and what to do →NVD recordCISA catalogmsrc.microsoft.commsrc.microsoft.com
Dec 13, 2022Microsoft Defender SmartScreen Security Feature Bypass VulnerabilityCVE-2022-44698 · Computers, phones & browsers · Microsoft · reported by secure@microsoft.comExploitedRansomwareMedium 5.4
Microsoft Defender SmartScreen contains a security feature bypass vulnerability that could allow an attacker to evade Mark of the Web (MOTW) defenses via a specially crafted malicious file.
- Product
- Defender
- On CISA’s list since
- Dec 13, 2022 (federal fix deadline Jan 3, 2023)
- What to do
- Attackers are using this now. Install Microsoft’s update today (ransomware groups use this one). If there is no update for your version, take the product off the internet or stop using it until there is.
Full record and what to do →NVD recordCISA catalogmsrc.microsoft.commsrc.microsoft.com
Nov 3, 2021Microsoft Defender Remote Code Execution VulnerabilityCVE-2021-1647 · Computers, phones & browsers · Microsoft · reported by secure@microsoft.comExploitedHigh 7.8
Microsoft Defender contains an unspecified vulnerability that allows for remote code execution.
- Product
- Defender
- On CISA’s list since
- Nov 3, 2021 (federal fix deadline Nov 17, 2021)
- What to do
- Attackers are using this now. Install Microsoft’s update today. If there is no update for your version, take the product off the internet or stop using it until there is.
Full record and what to do →NVD recordCISA catalogmsrc.microsoft.comportal.msrc.microsoft.com
Where this comes from: the exploited list is CISA’s Known Exploited Vulnerabilities catalog. Everything else is the whole National Vulnerability Database, where each record is published by the team that found the bug (Wordfence, Patchstack, WPScan, the vendors themselves and others); we show who. Exploit odds are FIRST’s EPSS, updated daily. Titles and categories are ours, so check the linked record before acting on a detail. For a write-up of the big ones, see our advisories. Every vendor, and every WordPress plugin and theme with a recorded flaw, also has its own page. All of it is free to reuse as JSON, CSV or RSS.
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