CVE-2026-32074 — Windows Projected File System Elevation of Privilege Vulnerability

Executive Summary

Double free 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

Less Likely

MS Exploit Likelihood

Category Elevation of Privilege

Weakness CWE-415: Double Free

Released Apr 14 2026

Last Updated Apr 14 2026

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

EPSS Score 0.00257 — 0.17403 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

0.00257

probability of exploitation in the next 30 days

0.17403 percentile - updated 2026-08-14

View on FIRST.org

Affected Products

23 affected products

Product	KB Article	Severity	Impact	Restart Required
Windows 10 Version 1809 for 32-bit Systems	`5082123 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 1809 for x64-based Systems	`5082123 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 21H2 for 32-bit Systems	`5082200 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 21H2 for ARM64-based Systems	`5082200 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 21H2 for x64-based Systems	`5082200 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 22H2 for 32-bit Systems	`5082200 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 22H2 for ARM64-based Systems	`5082200 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 22H2 for x64-based Systems	`5082200 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 Version 23H2 for ARM64-based Systems	`5082052 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 Version 23H2 for x64-based Systems	`5082052 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 Version 24H2 for ARM64-based Systems	`5083769 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 Version 24H2 for x64-based Systems	`5083769 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 Version 25H2 for ARM64-based Systems	`5083769 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 Version 25H2 for x64-based Systems	`5083769 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 Version 26H1 for ARM64-based Systems	`5083768 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 version 26H1 for x64-based Systems	`5083768 (Security Update)`	Important	Elevation of Privilege	Yes
Windows Server 2019	`5082123 (Security Update)`	Important	Elevation of Privilege	Yes
Windows Server 2019 (Server Core installation)	`5082123 (Security Update)`	Important	Elevation of Privilege	Yes
Windows Server 2022	`5082142 (Security Update)`	Important	Elevation of Privilege	Yes
Windows Server 2022 (Server Core installation)	`5082142 (Security Update)`	Important	Elevation of Privilege	Yes
Windows Server 2022, 23H2 Edition (Server Core installation)	`5082060 (Security Update)`	Important	Elevation of Privilege	Yes
Windows Server 2025	`5082063 (Security Update)`	Important	Elevation of Privilege	Yes
Windows Server 2025 (Server Core installation)	`5082063 (Security Update)`	Important	Elevation of Privilege	Yes

Patches

8 patches

Article	Type	Restart
`5082123`	Security Update	Yes
`5082200`	Security Update	Yes
`5082052`	Security Update	Yes
`5083769`	Security Update	Yes
`5083768`	Security Update	Yes
`5082142`	Security Update	Yes
`5082060`	Security Update	Yes
`5082063`	Security Update	Yes

Patch Diff

ghidriff · prjflt.sys (KB5083769)

Double free (CWE-415) in the Windows Projected File System minifilter prjflt.sys PrjfCreateUnionContext negative-path-cache hash table, local EoP. When PRJ_FLAG_USE_NEGATIVE_PATH_CACHE (Flags bit 0) is set, PrjfCreateUnionContext creates UnionContext->NegtiveHashTable via RtlCreateHashTableEx (initial size 0x2000). Inside RtlpCreateHashTable, for size>0x80 it ExAllocatePool2's a Directory then per-bucket SecondLevelDirs; if RtlpAllocateSecondLevelDir fails it jumps to RtlDeleteHashTable(HashTable), which frees HashTable->Directory (and second-level dirs) but does NOT NULL Directory. RtlCreateHashTableEx then returns false, so PrjfCreateUnionContext takes its error path and calls PrjfReleaseUnionContext, which (seeing Flags&1) calls RtlDeleteHashTable(&NegtiveHashTable) AGAIN, freeing the already-freed Directory a second time -> double free. Reachable unprivileged via ProjFS union-context creation; inducing the second-level-dir allocation to fail (pool pressure) triggers it. Diff of prjflt.sys 10.0.26100.8115 -> .8246 (Apr 14 2026, KB5083769) confirms the fix: gated behind CFR flag Feature_440600889, on the RtlCreateHashTableEx failure path PrjfCreateUnionContext clears the PRJ_FLAG_USE_NEGATIVE_PATH_CACHE bit (UnionContext->Flags &= 0xFFFFFFFE), so PrjfReleaseUnionContext's (Flags&1) guard is false and it does not delete the hash table a second time. Note: our diff shows Feature_440600889 (build/arch).

Pre-patch version 10.0.26100.8115 Download

Post-patch version 10.0.26100.8246 Download

Function	Address	Change	Note
`PrjfCreateUnionContext`	`code change`	code (clear negative-path-cache flag on hash-table failure, CFR-gated)	Pre: on RtlCreateHashTableEx failure (Directory freed but not NULL'd inside RtlDeleteHashTable), the error path calls PrjfReleaseUnionContext which, seeing Flags&1, calls RtlDeleteHashTable again -> double free of Directory. Post (Feature_440600889): clears Flags&1 (UnionContext->Flags & 0xFFFFFFFE) on the failure path so PrjfReleaseUnionContext skips the second RtlDeleteHashTable.
`Feature_440600889`	`gate`	added (CFR gate)	CFR flag gating the flag-clear on the hash-table-creation-failure path; original double-free path still ships when disabled.

View full diff report View RCA report

Attack Path

A failed second-level-dir allocation frees the hash-table Directory, then union-context release frees it again

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

No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.

Acknowledgments

ChenJian with Sea Security Orca Team

References

MSRC Advisory MITRE NVD