[KEV] CVE-2008-4250 -- CVSS 0.0 Vulnerability Briefing

[KEV] CVE-2008-4250 | CVSS 0.0 (Low) | Exploit: Operational

What Is It

CVE-2008-4250 is a remotely exploitable buffer overflow vulnerability in the Windows Server Service component of Microsoft Windows, affecting the RPC request handling path.

Technical Detail

The flaw resides in the Server Service's handling of RPC requests, where insufficient bounds checking during path canonicalization allows a specially crafted request to overflow a buffer. An unauthenticated remote attacker can send a malformed RPC packet to trigger this overflow without requiring any user interaction or prior authentication. Successful exploitation results in arbitrary code execution in the context of the affected service, which typically runs with SYSTEM-level privileges, granting full control of the target host.

Exploitation Status

The exploit for this vulnerability is rated as Operational, meaning functional exploit code exists and has been used in real-world attacks. CISA has confirmed active exploitation in the wild and added this vulnerability to the Known Exploited Vulnerabilities catalog on May 20, 2026. This vulnerability was previously associated with the Conficker worm and has a long history of weaponized use, making reliable exploitation tooling widely available.

Who Is Targeting This

No specific threat actor attribution is confirmed in current reporting. However, given the vulnerability's history and the availability of operational exploit code, opportunistic threat actors, ransomware operators, and automated scanning infrastructure are all plausible sources of exploitation activity targeting unpatched systems.

What To Do

Microsoft released MS08-067 to address this vulnerability in October 2008. Organizations should verify that this patch has been applied to all in-scope Windows systems, as legacy and isolated environments may have missed it. Per CISA's Known Exploited Vulnerabilities catalog, federal agencies are required to remediate this vulnerability by the binding directive deadline associated with the May 20, 2026 addition date. Where patching is not immediately possible, blocking inbound RPC traffic (TCP port 445 and 139) at network boundaries can reduce exposure. Organizations should also audit for signs of lateral movement or unauthorized service execution consistent with post-exploitation activity on any systems that may have been exposed.