CVE-2018-8639
An elevation of privilege vulnerability exists in Windows when the Win32k component fails to properly handle objects in memory, aka "Win32k Elevation of Privilege Vulnerability." This affects Windows 7, Windows Server 2012 R2, Windows RT 8.1, Windows Server 2008, Windows Server 2019, Windows Server 2012, Windows 8.1, Windows Server 2016, Windows Server 2008 R2, Windows 10, Windows 10 Servers. This CVE ID is unique from CVE-2018-8641.
do firstApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Can a WAF block it? No. The attack needs local access to the machine, so a WAF is not on its path.
Also consider: patch
Based on the attack vector (local or physical access). We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Is CVE-2018-8639 being exploited?
Yes. CVE-2018-8639 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.
How severe is CVE-2018-8639?
CVE-2018-8639 is rated High with a CVSS score of 7.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2018-8639?
Yes. A fix has been recorded for CVE-2018-8639. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2018-8639 affect?
CVE-2018-8639 affects microsoft:windows_10_1507, microsoft:windows_10_1607, microsoft:windows_10_1703, microsoft:windows_10_1709, and 9 further products or versions. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
- affected32-bit Systems
- affectedVersion 1607 for 32-bit Systems
- affectedVersion 1607 for x64-based Systems
- affectedVersion 1703 for 32-bit Systems
- affectedVersion 1703 for x64-based Systems
- affectedVersion 1709 for 32-bit Systems
- affectedVersion 1709 for ARM64-based Systems
- affectedVersion 1709 for x64-based Systems
- affectedVersion 1803 for 32-bit Systems
- affectedVersion 1803 for ARM64-based Systems
- affectedVersion 1803 for x64-based Systems
- affectedVersion 1809 for 32-bit Systems
- affectedVersion 1809 for ARM64-based Systems
- affectedVersion 1809 for x64-based Systems
- affectedx64-based Systems
- affectedversion 1709 (Server Core Installation)
- affectedversion 1803 (Server Core Installation)
- affected32-bit Systems Service Pack 1
- affectedx64-based Systems Service Pack 1
- affected32-bit systems
- affectedx64-based systems
- affectedWindows RT 8.1
- affected32-bit Systems Service Pack 2
- affected32-bit Systems Service Pack 2 (Server Core installation)
- affectedItanium-Based Systems Service Pack 2
- affectedx64-based Systems Service Pack 2
- affectedx64-based Systems Service Pack 2 (Server Core installation)
- affectedItanium-Based Systems Service Pack 1
- affectedx64-based Systems Service Pack 1
- affectedx64-based Systems Service Pack 1 (Server Core installation)
- affected(Server Core installation)
- affected(Server Core installation)
- affected(Server Core installation)
- affected(Server Core installation)
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
public exploits
Unvetted proof-of-concept code on GitHub: 2 GitHub proofs of concept
- ze0r/CVE-2018-8639-exp · 125 ★
- timwhitez/CVE-2018-8639-EXP · 5 ★
Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.
cisa ssvc
- exploitation
- active
- automatable
- no
- technical impact
- total
Assessed by CISA 3 Mar 2025 (SSVC 2.0.3).
timeline
- 12 Dec 2018Published
- 5 Mar 2019First proof-of-concept repository on GitHub (unvetted) · 83 days (about 3 months) later
- 3 Mar 2025Added to CISA KEV (exploited in the wild) · 2,190 days (about 6 years) later
- 3 Mar 2025CISA SSVC assessment: exploitation active · 1 day later
- 24 Mar 2025CISA remediation due date (US federal agencies) · 20 days later
- 21 Oct 2025CVE record last updated · 212 days (about 7 months) later
- 2 Nov 2026Analysed by vulneraibility.com · 377 days (about 1 year) later
- Linksecurityfocus.com /bid/106093
- Linkportal.msrc.microsoft.com /en-US/security-guidance/advisory/CVE-2018-8639
- Linkcisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-8639
sources
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA KEV catalog: exploitation, date added, due date
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
- PoC-in-GitHub: GitHub repositories that claim a proof of concept
- Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.