ZDI-26-274: Microsoft Qlib fit Deserialization of Untrusted Data Remote Code Execution Vulnerability
This vulnerability allows remote attackers to execute arbitrary code on affected installations of Microsoft Qlib. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The ZDI has assigned a CVSS rating of 7.8.
AI Analysis
Technical Summary
The Microsoft Qlib fit function contains a deserialization vulnerability caused by insufficient validation of untrusted input. This flaw enables remote attackers to execute arbitrary code by supplying crafted data that is deserialized improperly. Exploitation requires user interaction, such as opening a malicious file or visiting a malicious webpage. The vulnerability allows code execution with root-level privileges, posing a critical security risk. The issue was reported to Microsoft on May 22, 2025, and patched on May 31, 2025. The advisory was publicly released on April 15, 2026, with a CVSS base score of 7.8 (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).
Potential Impact
Remote attackers can execute arbitrary code with root privileges on affected Microsoft Qlib installations by exploiting this vulnerability. This can lead to full system compromise, including confidentiality, integrity, and availability impacts. Exploitation requires user interaction but does not require prior authentication.
Mitigation Recommendations
An official fix for this vulnerability was released by Microsoft on May 31, 2025. Users and administrators should apply the available patch immediately to remediate this issue. Since the vulnerability requires user interaction, educating users to avoid opening untrusted files or visiting suspicious websites can reduce risk but does not replace patching.
ZDI-26-274: Microsoft Qlib fit Deserialization of Untrusted Data Remote Code Execution Vulnerability
Description
This vulnerability allows remote attackers to execute arbitrary code on affected installations of Microsoft Qlib. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The ZDI has assigned a CVSS rating of 7.8.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Microsoft Qlib fit function contains a deserialization vulnerability caused by insufficient validation of untrusted input. This flaw enables remote attackers to execute arbitrary code by supplying crafted data that is deserialized improperly. Exploitation requires user interaction, such as opening a malicious file or visiting a malicious webpage. The vulnerability allows code execution with root-level privileges, posing a critical security risk. The issue was reported to Microsoft on May 22, 2025, and patched on May 31, 2025. The advisory was publicly released on April 15, 2026, with a CVSS base score of 7.8 (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).
Potential Impact
Remote attackers can execute arbitrary code with root privileges on affected Microsoft Qlib installations by exploiting this vulnerability. This can lead to full system compromise, including confidentiality, integrity, and availability impacts. Exploitation requires user interaction but does not require prior authentication.
Mitigation Recommendations
An official fix for this vulnerability was released by Microsoft on May 31, 2025. Users and administrators should apply the available patch immediately to remediate this issue. Since the vulnerability requires user interaction, educating users to avoid opening untrusted files or visiting suspicious websites can reduce risk but does not replace patching.
Technical Details
- Article Source
- {"url":"http://www.zerodayinitiative.com/advisories/ZDI-26-274/","fetched":true,"fetchedAt":"2026-05-26T19:58:32.421Z","wordCount":195}
Threat ID: 6a15fc93e29bf47b5055e080
Added to database: 5/26/2026, 8:03:31 PM
Last enriched: 5/26/2026, 8:08:58 PM
Last updated: 5/27/2026, 5:03:05 AM
Views: 4
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