CVE-2008-4250

CRITICAL(9.8)KEVLikely Exploited

Microsoft Windows Buffer Overflow Vulnerability

Description

CVE-2008-4250, addressed by Microsoft bulletin MS08-067, is a critical-severity buffer overflow vulnerability in the Windows Server service. A crafted RPC request triggers a memory buffer overflow during path canonicalization, allowing remote, unauthenticated attackers to execute arbitrary code on affected Windows systems. This is the vulnerability famously exploited by the Gimmiv.A trojan in October 2008 and subsequently weaponized by the Conficker worm, making it one of the most impactful remote code execution flaws in Windows history. With a CVSS score of 9.8, an EPSS score of 92% (99.7th percentile), and a CISA KEV listing, CVE-2008-4250 remains a serious risk on any unpatched or end-of-life Windows host.

KEV Information

Vendor
Microsoft
Product
Windows
Date Added
May 20, 2026
Due Date
June 3, 2026
Required Action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

CVSS Score

Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HOpen in Calculator
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9

CWEs

Affected Products

VendorProductVersion
microsoftwindows 2000-
microsoftwindows server 2003-
microsoftwindows server 2008-
microsoftwindows vista-
microsoftwindows xp-

References

Weakness Type

CWE-94: Improper Control of Generation of Code ('Code Injection')

In the Windows Server service, the overflow during path canonicalization lets an attacker inject and execute code of their choosing via a crafted RPC request, so the consequence of the memory corruption is full code injection into a privileged system process.

Learn more: CWE-94 — Improper Control of Generation of Code ('Code Injection')

CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer

The root cause is a memory buffer error: the Server service fails to properly bound operations during path canonicalization of an RPC request, allowing an out-of-bounds write that corrupts memory and enables control of execution flow.

Learn more: CWE-119 — Improper Restriction of Operations within the Bounds of a Memory Buffer

Impact Analysis

CVE-2008-4250 carries a CVSS 3.1 score of 9.8 (CRITICAL). It is remotely exploitable over the network with low attack complexity, requires no authentication and no user interaction, and fully compromises the confidentiality, integrity, and availability of the affected host because exploitation yields arbitrary code execution in the context of the Server service. Historically this flaw enabled self-propagating worms — most notably Conficker — to spread across networks without any user action, infecting millions of machines. The EPSS score of 92% (99.7th percentile) reflects near-certain exploitation activity, and the CISA KEV listing confirms it remains exploited in the wild; any legacy Windows 2000, XP, Server 2003, Vista, or Server 2008 system reachable on a network is at acute risk.

Exploit Maturity

CVE-2008-4250 has an extremely mature exploit landscape. Public exploit code is widely available, including modules on Exploit-DB and additional Exploit-DB entries, and the flaw is incorporated into common penetration-testing frameworks. CISA confirms active exploitation through its KEV listing, and the EPSS score of 92% (99.7th percentile) indicates near-certain ongoing exploitation. Because this vulnerability powered the Conficker worm and the Gimmiv.A trojan, reliable weaponized exploits have circulated for well over a decade; any exposed unpatched host should be considered at immediate risk of automated, wormable compromise.

Remediation

  1. Apply the MS08-067 update or remove the affected asset from the network as mandated by the CISA KEV deadline of 2026-06-03: install the patch from Microsoft Security Bulletin MS08-067 for all affected Windows versions.
  2. For end-of-life systems (Windows 2000, XP, Server 2003) that can no longer receive updates, isolate or decommission them — these platforms are unsupported and should not remain reachable on production networks.
  3. As an interim mitigation, block TCP ports 139 and 445 at the network perimeter and between network segments to limit RPC/SMB reachability to the Server service, and disable the Server service where it is not required.
  4. Monitor for exploitation by watching for anomalous RPC traffic to the Server service and for worm-like lateral movement, and check hosts for indicators of Conficker and related malware.
  5. As long-term hardening against memory buffer and code injection flaws, migrate off unsupported operating systems, enforce network segmentation, and ensure exploit-mitigation features (DEP/ASLR) are enabled on any remaining legacy systems.

Technical Details

CVE-2008-4250 is a buffer overflow (CWE-119) in the Server service of Microsoft Windows (2000 SP4; XP SP2/SP3; Server 2003 SP1/SP2; Vista Gold/SP1; Server 2008; Windows 7 Pre-Beta). A specially crafted RPC request triggers an overflow during path canonicalization, corrupting memory in a way that allows the attacker to inject and execute arbitrary code (CWE-94) in the privileged context of the service. Because the Server service is reachable over SMB/RPC on TCP ports 139 and 445 with no authentication, the vulnerability is trivially wormable, which is exactly how the Conficker worm and the Gimmiv.A trojan propagated. The CVSS vector (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) reflects a network-reachable, low-complexity, unauthenticated attack with full impact across confidentiality, integrity, and availability.

Frequently Asked Questions

Is CVE-2008-4250 being actively exploited?

Yes. CVE-2008-4250 is on the CISA Known Exploited Vulnerabilities catalog and carries an EPSS score of 92% (99.7th percentile). It was the basis for the Gimmiv.A trojan and the Conficker worm, and weaponized exploits remain in wide circulation, so any exposed unpatched host faces near-certain exploitation.

What products are affected by CVE-2008-4250?

The vulnerability affects the Server service in Microsoft Windows 2000, Windows XP, Windows Server 2003, Windows Vista, and Windows Server 2008. Several of these (Windows 2000, XP, Server 2003) are end-of-life and no longer receive security updates.

How do I fix CVE-2008-4250?

Apply the Microsoft MS08-067 security update on all affected supported systems. For end-of-life platforms, isolate or decommission them, and as an interim measure block TCP ports 139 and 445 and disable the Server service where it is not needed.

How severe is CVE-2008-4250?

CVE-2008-4250 is rated CRITICAL with a CVSS 3.1 score of 9.8. It allows remote, unauthenticated, wormable code execution on affected Windows systems and is historically significant as the flaw behind the Conficker worm, making it one of the most dangerous Windows vulnerabilities ever disclosed.

CVSS Score

9.8
CRITICAL(9.8)

EPSS Score

EPSS Score98.75%
EPSS Percentile99.9%

Dates

PublishedOctober 23, 2008
Last ModifiedJune 16, 2026
StatusAnalyzed
CVSS Versionv3.1

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