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Windows Projected File System

CVE-2025-62462 — Windows Projected File System Elevation of Privilege Vulnerability

Important CVSS 7.8 EPSS 0.00392 🔬 Patch diffed 2025-12 archive

Executive Summary

Buffer over-read in Windows Projected File System allows an authorized attacker to elevate privileges locally.

Overview

7.8
CVSS HIGH
Important
MS Severity
Not Exploited
MS Exploit Status
Exploitation Unlikely
MS Exploit Likelihood
Category Elevation of Privilege
Weakness CWE-126: Buffer Over-read
Released Dec 9 2025
Last Updated Dec 9 2025
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.00392 — 0.3229 percentile
NVD CVSS 7.8 HIGH — matches MSRC

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
ATTACK VECTOR
Local
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
Low
USER INTERACTION
None
SCOPE
Unchanged
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
High
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 6.8

EPSS Score

0.00392
probability of exploitation in the next 30 days
0.3229 percentile - updated 2026-08-14
View on FIRST.org

Affected Products

13 affected products
Product KB Article Severity Impact Restart Required
Windows 10 Version 1809 for 32-bit Systems 5071544 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 1809 for x64-based Systems 5071544 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 21H2 for 32-bit Systems 5071546 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 21H2 for ARM64-based Systems 5071546 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 21H2 for x64-based Systems 5071546 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 22H2 for 32-bit Systems 5071546 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 22H2 for ARM64-based Systems 5071546 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 22H2 for x64-based Systems 5071546 (Security Update) Important Elevation of Privilege Yes
Windows 11 Version 23H2 for ARM64-based Systems 5071417 (Security Update) Important Elevation of Privilege Yes
Windows 11 Version 23H2 for x64-based Systems 5071417 (Security Update) Important Elevation of Privilege Yes
Windows 11 Version 24H2 for ARM64-based Systems 5072033 (Security Update) 5072014 (Security Hotpatch Update) Important Elevation of Privilege 5068861 5068966 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26100.7462 10.0.26100.7392 Yes None Windows 11 Version 24H2 for x64-based Systems 5072033 (Security Update) 5072014 (Security Hotpatch Update) Important Elevation of Privilege 5068861 5068966 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26100.7462 10.0.26100.7392 Yes None Windows 11 Version 25H2 for ARM64-based Systems 5072033 (Security Update) 5072014 (Security Hotpatch Update) Important Elevation of Privilege 5068861 5068966 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26200.7462 10.0.26200.7392 Yes None Windows 11 Version 25H2 for x64-based Systems 5072033 (Security Update) 5072014 (Security Hotpatch Update) Important Elevation of Privilege 5068861 5068966 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26200.7462 10.0.26200.7392 Yes None Windows Server 2019 5071544 (Security Update) Important Elevation of Privilege Yes
Windows Server 2019 (Server Core installation) 5071544 (Security Update) Important Elevation of Privilege Yes
Windows Server 2022 5071547 (Security Update) 5071413 (Security Hotpatch Update) Important Elevation of Privilege 5068787 5068840 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.20348.4529 10.0.20348.4467 Yes None Windows Server 2022 (Server Core installation) 5071547 (Security Update) 5071413 (Security Hotpatch Update) Important Elevation of Privilege 5068787 5068840 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.20348.4529 10.0.20348.4467 Yes None Windows Server 2022, 23H2 Edition (Server Core installation) 5071542 (Security Update) Important Elevation of Privilege Yes

Patches

4 patches
Article Type Restart
5071544 Security Update Yes
5071546 Security Update Yes
5071417 Security Update Yes
5071542 Security Update Yes

Patch Diff

ghidriff · prjflt.sys (KB5072033)

Buffer over-read (CWE-126) in the Windows Projected File System minifilter prjflt.sys PrjfCompleteCommandHandler, local EoP info-leak. PrjfCompleteCommandHandler (a PrjfPortMessage handler) does memmove(CommandEntry->OutputEntry->OutputBuffer, MessageData->ResultBuffer, MessageData->ResultLength). MessageData is a pool buffer whose contents (including ResultLength, at param_2[0x18]) are copied from user input at the top of PrjfPortMessage. PRE: ResultLength is not validated against the actual MessageData allocation, so a large ResultLength copies adjacent pool memory past the buffer into OutputBuffer (a directory-info structure), from where it is later returned to the caller - a kernel pool info-leak. Diff of prjflt.sys 10.0.26100.7309 -> .7462 (Dec 9 2025, KB5072033) confirms the fix: gated behind CFR flag Feature_2814151992, PrjfCompleteCommandHandler now computes uVar1 = ResultLength + 100 (0x64 header), rejects it on integer overflow (uVar1 < ResultLength) and rejects it when the declared DataSize (*param_2) < uVar1, so an over-large ResultLength is refused before the copy.

Pre-patch version 10.0.26100.7309 Download
Post-patch version 10.0.26100.7462 Download
Function Address Change Note
PrjfCompleteCommandHandler code change code (bounds/validation added, CFR-gated) Pre: memmove(OutputBuffer, MessageData->ResultBuffer, ResultLength) with user-controlled ResultLength (param_2[0x18]) unchecked against the MessageData pool size -> over-read of adjacent pool. Post (Feature_2814151992): uVar1=ResultLength+0x64; if(uVar1<ResultLength) reject (overflow); if(*param_2 /*DataSize*/ < uVar1) reject; then copy.
Feature_2814151992 gate added (CFR gate) CFR flag gating the added validation; the original unchecked path still ships when disabled.
View full diff report View RCA report

Attack Path

A user-controlled ResultLength is memmove'd from the message pool buffer without a size check, over-reading adjacent pool into the returned directory buffer

Attack path for CVE-2025-62462 A user-controlled ResultLength is memmove'd from the message pool buffer without a size check, over-reading adjacent pool into the returned directory buffer 01 — ENTRY Local user sends a completed-command message to the ProjFS port prjflt.sys PrjfPortMessage copies the user message into a pool buffer and dispatches PrjfCompleteCommandHandler. AV:L/PR:L/AC:L. 02 — CONTROLLED INPUT Sets MessageData->ResultLength larger than the MessageData allocation ResultLength (param_2[0x18]) is attacker-controlled; e.g. buffer is 0x100 but ResultLength is 0x200. 03 — MISSING CHECK memmove copies ResultLength bytes with no bound check (CWE-126) memmove(OutputEntry->OutputBuffer, MessageData->ResultBuffer, ResultLength) reads past the pool buffer into adjacent pool. 04 — PATH Leaked pool bytes land in the directory-info OutputBuffer The over-read data fills FILE_ID_EXTD_DIR_INFORMATION fields (e.g. FileName) of the enumeration result. 05 — PRIMITIVE Adjacent kernel pool disclosed to the caller -> info-leak / EoP The Dec 2025 fix (Feature_2814151992) rejects ResultLength+0x64 on overflow or when it exceeds DataSize before the copy.

Derived from the patch delta: the checks added by the vendor identify which fields crossed a trust boundary unvalidated. Reachability and privilege are taken from the call chain in the RCA report.

Known Exploits

Acknowledgments

ChenJian with Sea Security Orca Team

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