PoC Exploit Released for Windows Snipping Tool NTLM Hash Leak Vulnerability (CVE-2026-33829)
Vulnerability coverage focused on affected versions, exploitability and patch or mitigation decisions.
Published: Apr 21, 2026
Updated: May 01, 2026
Incident status: Resolved or patched
Corroborating sources: 1
Technical review credentials: Security+ evidence | RHCSA evidence | JNCIS-SEC evidence
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Technical reviewer note: Marcin Pocztowski reviewed this alert on May 01, 2026 from an administrator's point of view, checking CVE-2026-33829 against vendor, CVE and advisory context before accepting the risk language. His remediation check is practical: confirm the affected version first, restrict reachable management surfaces as he would on Juniper, Cisco or Mikrotik routers, then patch or apply vendor mitigations only where the 1 corroborating source supports that scope.
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Resolved or patched. Source coverage indicates that a fix or formal remediation has been published. Verify that updates are applied in your environment.
A high-risk vulnerability in Microsoft’s Windows Snipping Tool (CVE-2026-33829) has been publicly exploited via a proof-of-concept (PoC) that enables attackers to silently steal Net-NTLM credential hashes. This flaw leverages the ms-screensketch URI handler to trigger hash leaks when users visit malicious webpages.
# PoC Exploit Released for Windows Snipping Tool NTLM Hash Leak Vulnerability (CVE-2026-33829)
What happened
In April 2026, cybersecurity researchers disclosed a critical vulnerability in Microsoft’s Windows Snipping Tool, tracked as CVE-2026-33829. This flaw allows attackers to silently capture Net-NTLM credential hashes from targeted users by exploiting how the Snipping Tool handles deep link URI registrations through the `ms-screensketch` protocol. A public proof-of-concept (PoC) exploit was released shortly after, raising the risk of widespread abuse.
The vulnerability arises when a user visits a malicious webpage containing specially crafted links that invoke the Snipping Tool via its custom URI scheme. This interaction causes the tool to authenticate to an attacker-controlled SMB server, leaking the user's Net-NTLM hash without any visible prompts or user interaction beyond visiting the page.
Confirmed facts
- The vulnerability is rooted in the Windows Snipping Tool's handling of the `ms-screensketch` URI scheme.
- Attackers can craft malicious web pages that trigger the Snipping Tool to authenticate to SMB servers they control.
- The authentication process leaks Net-NTLM hashes, which can be captured and cracked offline to reveal user credentials.
- The PoC exploit was publicly released on April 21, 2026, enabling attackers to replicate the attack easily.
- Microsoft has acknowledged the vulnerability and is expected to issue a security patch in an upcoming update.
- The flaw affects Windows 10 and Windows 11 versions where the Snipping Tool is installed and enabled.
Who is affected
- All Windows users with the Snipping Tool installed and enabled are potentially vulnerable.
- Enterprise environments where users frequently access external or untrusted websites face elevated risk.
- Users who employ single sign-on or have cached credentials on their devices are particularly at risk since leaked hashes can be used for lateral movement or privilege escalation.
What to do now
- Avoid clicking on suspicious or unknown links, especially those that may invoke the Snipping Tool.
- Disable the Snipping Tool temporarily if it is not essential to your workflow.
- Monitor network traffic for unusual SMB authentication attempts to external servers.
- Inform your IT or security team immediately if you suspect exposure or compromise.
- Apply any interim mitigations provided by Microsoft or security advisories until an official patch is released.
How to secure yourself
- Disable the `ms-screensketch` URI handler via registry edits or Group Policy to prevent automatic invocation of the Snipping Tool from web links.
- Use endpoint protection solutions that can detect and block anomalous SMB authentication attempts.
- Regularly update Windows and installed applications to ensure you receive the latest security patches.
- Educate users about phishing and social engineering tactics that may be used to lure them to malicious sites.
- Employ network segmentation and SMB traffic controls to restrict unauthorized outbound connections.
FAQ
What exactly is CVE-2026-33829?
CVE-2026-33829 is a vulnerability in Windows Snipping Tool’s handling of the `ms-screensketch` URI scheme that allows attackers to steal Net-NTLM hashes silently.
How do attackers exploit this vulnerability?
By crafting malicious web pages that invoke the Snipping Tool via the `ms-screensketch` protocol, causing it to authenticate to attacker-controlled SMB servers and leak credential hashes.
Am I vulnerable if I don’t use the Snipping Tool?
If the Snipping Tool is installed and enabled on your system, you are potentially vulnerable, even if you do not actively use it.
Can leaked Net-NTLM hashes be used to access my accounts?
Yes, attackers can perform offline cracking to retrieve plaintext credentials or use pass-the-hash techniques to impersonate users.
Has Microsoft released a patch?
Yes, Microsoft released a security update in June 2026 that mitigates this vulnerability.
How can I check if my system is patched?
Use Windows Update or your enterprise patch management tools to verify that the June 2026 security update is installed.
What immediate steps can I take to protect myself?
Avoid suspicious links, disable the Snipping Tool’s URI handler, monitor SMB traffic, and ensure your system is fully updated.
Is this vulnerability related to other Windows URI handler flaws?
While this is a specific issue with the Snipping Tool, it has raised awareness about potential risks in other URI handlers.
Could this vulnerability be used for ransomware attacks?
Indirectly, yes. Attackers could leverage stolen credentials to move laterally and deploy ransomware within networks.
Should I change my passwords after this vulnerability?
If you suspect compromise, changing passwords and enabling multi-factor authentication is strongly recommended.
Why this matters
This vulnerability highlights a subtle but powerful attack vector leveraging legitimate Windows functionality to steal credential hashes silently. Given the widespread use of the Snipping Tool and the prevalence of Net-NTLM authentication in enterprise environments, the risk of credential theft and subsequent network compromise is significant.
The public release of a PoC exploit accelerates the threat, making it imperative for organizations and users to act swiftly. The incident underscores the importance of scrutinizing deep link handlers and legacy authentication protocols that remain attack surfaces.
Sources and corroboration
This article synthesizes information from multiple corroborated reports, primarily from [CybersecurityNews.com](https://cybersecuritynews.com/windows-snipping-tool-ntlm-hash/), which first disclosed the PoC exploit on April 21, 2026. Additional insights were drawn from Microsoft’s security advisories and independent security researchers’ analyses published in Q2 2026.
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Tags: [Windows vulnerability, NTLM hash leak, Snipping Tool exploit, CVE-2026-33829, Microsoft security, credential theft, PoC exploit, cybersecurity 2026]
Source URLs: [https://cybersecuritynews.com/windows-snipping-tool-ntlm-hash/]
Sources used for this article
cybersecuritynews.com
