Executive brief
A security vulnerability exists in a core Windows component responsible for handling internet communications. An attacker who already has basic access to a computer could exploit this flaw to gain full administrative control over the system. This could allow them to steal sensitive data, install malicious software, or disrupt business operations.
Technical details
This vulnerability is classified as an integer overflow or wraparound (CWE-190) within the Windows Internet library (wininet.dll), which may also lead to a use-after-free condition (CWE-416). The flaw is exploitable by a local attacker with low-level privileges who can execute a specially crafted application. Successful exploitation allows the attacker to bypass security boundaries and execute code with elevated system privileges. Microsoft has released security updates to address this issue; users should apply the latest Windows cumulative updates to mitigate the risk.
Affected products
- Microsoft Windows Internet (wininet.dll)
Timeline
- 2026-06-09: disclosed
- 2026-06-09: advisory