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…
High
Known exploited
- Severity
- 7.8 / 10
- High · CVSS 3.1
- Exploit chance (EPSS)
- 22.18%
- Chance of exploitation in the next 30 days. Higher than 97.67% of scored vulnerabilities.
- Known exploited
- Yes
- In CISA's catalog since Mar 3, 2025
- Fix
- None yet
- No fixed version published
Exploited in the wild. Microsoft Windows Win32k Improper Resource Shutdown or Release Vulnerability (Microsoft Windows). 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. Due for U.S. federal agencies by Mar 24, 2025. Known to be used in ransomware campaigns.
Description
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.
How to fix
No fixed version has been published yet. Until one is, remove or replace the package, or turn off or isolate the affected feature. This page updates when a fix ships.
Severity breakdown
CVSS 3.1 7.8
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Weakness
CWE-404: Improper Resource Shutdown or Release
The product does not release or incorrectly releases a resource before it is made available for re-use.
How to prevent it
- Requirements: Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, languages such as Java, Ruby, and Lisp perform automatic garbage collection that releases memory for objects that have been deallocated.
- Implementation: It is good practice to be responsible for freeing all resources you allocate and to be consistent with how and where you free memory in a function. If you allocate memory that you intend to free upon completion of the function, you must be sure to free the memory at all exit points for that function including error conditions.
- Implementation: Memory should be allocated/freed using matching functions such as malloc/free, new/delete, and new[]/delete[].
- Implementation: When releasing a complex object or structure, ensure that you properly dispose of all of its member components, not just the object itself.
CWE-404: Improper Resource Shutdown or Release
The product does not release or incorrectly releases a resource before it is made available for re-use.
How to prevent it
- Requirements: Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, languages such as Java, Ruby, and Lisp perform automatic garbage collection that releases memory for objects that have been deallocated.
- Implementation: It is good practice to be responsible for freeing all resources you allocate and to be consistent with how and where you free memory in a function. If you allocate memory that you intend to free upon completion of the function, you must be sure to free the memory at all exit points for that function including error conditions.
- Implementation: Memory should be allocated/freed using matching functions such as malloc/free, new/delete, and new[]/delete[].
- Implementation: When releasing a complex object or structure, ensure that you properly dispose of all of its member components, not just the object itself.
References
Advisories
Other links
Timeline
- Published
- Added to CISA's Known Exploited Vulnerabilities catalog
- Remediation due for U.S. federal agencies
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| PYSEC-2026-4319 A security flaw has been discovered in vllm-project vLLM up to 0.31.0. | Medium | Same weakness, CWE-404 |
| PYSEC-2026-4186 A flaw has been found in vllm-project vLLM up to 0.26.0. | Medium | Same weakness, CWE-404 |
| GHSA-9x8q-7h8h-wcw9 aiohttp: Payload Response Resources Are Not Closed After Mid-Body Disconnect | High | Same weakness, CWE-404 |
| GHSA-98f3-hwg4-4rf7 vllm has Improper Resource Shutdown or Release | Medium | Same weakness, CWE-404 |
| GHSA-w9m9-85wc-3x92 postcss-selector-parser allows denial of service through uncontrolled AST recursion | Low | Same weakness, CWE-404 |
| GHSA-3298-56p6-rpw2 OpenClaw has incomplete Fix for CVE-2026-27486: Unvalidated SIGKILL in `!stop` Chat Command via `shell-utils.ts` | Medium | Same weakness, CWE-404 |
| GHSA-h656-5vcf-cm23 OpenClaw: Unauthorized Telegram Senders Trigger Media Download and Disk Write Before Access Check | Medium | Same weakness, CWE-404 |
| GHSA-rxpr-wq63-jr7p Open Babel has a NULL pointer dereference in CDXML OBAtom::GetExplicitValence | Medium | Same weakness, CWE-404 |
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