Privilege escalation via splwow64 pointer dereference
Published Jun 9, 2020 · Updated Oct 21, 2025
Memory corruption in Microsoft Windows splwow64.exe allows local users to execute code in its medium-integrity process. GdiPrinterThunk accepts attacker-controlled pointers from a crafted type 0x6D LPC DocumentEvent message and passes them to memcpy as its source, destination, and size. Exploitation requires low-privileged code execution and shared memory with splwow64; success provides arbitrary memory read and write access in the medium-integrity process.
Summary
What happened
Memory corruption in Microsoft Windows splwow64.exe allows local users to execute code in its medium-integrity process. GdiPrinterThunk accepts attacker-controlled pointers from a crafted type 0x6D LPC DocumentEvent message and passes them to memcpy as its source, destination, and size. Exploitation requires low-privileged code execution and shared memory with splwow64; success provides arbitrary memory read and write access in the medium-integrity process.
The record
- CVE
- CVE-2020-0986
- Published
- Jun 9, 2020
- Updated
- Oct 21, 2025
- Vendor
- Microsoft
- Product
- Windows 10 Version 1909
- Classifications
- CWE-787, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 9, 2020CVE publishedPublication date reported by the CVE source.
- Nov 3, 2021Exploitation reportedCISA Known Exploited Vulnerabilities catalog entry
- Oct 21, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=unspecified
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- Project Zero minimized splwow64 proof of conceptproof of concept · demonstrated
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Reported exploitation
- CISA Known Exploited Vulnerabilities catalog entryknown exploited catalog
Technologies
Your stack
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Your stack
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