CVE-2024-30085 — Windows Cloud Files Mini Filter Driver Elevation of Privilege Vulnerability

Executive Summary

None

Overview

7.8

CVSS HIGH

Important

MS Severity

Not Exploited

MS Exploit Status

More Likely

MS Exploit Likelihood

Category Elevation of Privilege

Weakness CWE-122: Heap-based Buffer Overflow

Released Jun 11 2024

Last Updated Jun 11 2024

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

EPSS Score 0.15127 — 0.96381 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:P/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

Proof-of-Concept

REMEDIATION LEVEL

Official Fix

REPORT CONFIDENCE

Confirmed

Temporal Score: 7.0

EPSS Score

0.15127

probability of exploitation in the next 30 days

0.96381 percentile - updated 2026-07-25

View on FIRST.org

Affected Products

18 affected products

Product	KB Article	Severity	Impact	Restart Required
Windows 10 Version 1809 for 32-bit Systems	`5039217 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 1809 for ARM64-based Systems	`5039217 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 1809 for x64-based Systems	`5039217 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 21H2 for 32-bit Systems	`5039211 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 21H2 for ARM64-based Systems	`5039211 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 21H2 for x64-based Systems	`5039211 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 22H2 for 32-bit Systems	`5039211 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 22H2 for ARM64-based Systems	`5039211 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 22H2 for x64-based Systems	`5039211 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 version 21H2 for ARM64-based Systems	`5039213 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 version 21H2 for x64-based Systems	`5039213 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 Version 22H2 for ARM64-based Systems	`5039212 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 Version 22H2 for x64-based Systems	`5039212 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 Version 23H2 for ARM64-based Systems	`5039212 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 Version 23H2 for x64-based Systems	`5039212 (Security Update)`	Important	Elevation of Privilege	Yes
Windows Server 2019	`5039217 (Security Update)`	Important	Elevation of Privilege	Yes
Windows Server 2019 (Server Core installation)	`5039217 (Security Update)`	Important	Elevation of Privilege	Yes
Windows Server 2022 5039227 (Security Update) 5039330 (Security Hotpatch Update) Important Elevation of Privilege 5037782 5037848 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C 10.0.20348.2527 10.0.20348.2522 Yes 5039227 Windows Server 2022 (Server Core installation) 5039227 (Security Update) 5039330 (Security Hotpatch Update) Important Elevation of Privilege 5037782 5037848 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C 10.0.20348.2527 10.0.20348.2522 Yes 5039227 Windows Server 2022, 23H2 Edition (Server Core installation)	`5039236 (Security Update)`	Important	Elevation of Privilege	Yes

Patches

5 patches

Article	Type	Restart
`5039217`	Security Update	Yes
`5039211`	Security Update	Yes
`5039213`	Security Update	Yes
`5039212`	Security Update	Yes
`5039236`	Security Update	Yes

Patch Diff

ghidriff · cldflt.sys (KB5039211)

Heap-based buffer overflow in cldflt.sys HsmIBitmapNORMALOpen. Allocates 0x1000-byte HsBm paged pool buffer then copies user-controlled reparse data (HSM_DATA BtRp bitmap element) without bounds check. memcpy_size derives from 16-bit Length field in cloud filter reparse point structure. Trigger: CfRegisterSyncRoot + FSCTL_SET_REPARSE_POINT_EX with IO_REPARSE_TAG_CLOUD_6, then reopen file. Full exploit: two-trigger WNF corruption + ALPC handle table spray + PipeAttribute arbitrary read + token privilege overwrite. CVSS 7.8 local EoP to SYSTEM.

Pre-patch version 10.0.22621.3593

Post-patch version 10.0.22621.3810

Function	Address	Change	Note
`HsmIBitmapNORMALOpen`		code (bounds check added before memcpy)	Added cmp r14d, 0x1000 check before memcpy of user-controlled reparse data into 0x1000-byte HsBm paged pool allocation. Pre-patch: no size validation, allowing overflow. Post-patch: rejects memcpy_size > 0x1000 with STATUS_BUFFER_OVERFLOW error.

View full diff report View RCA report Download PoC

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

Gwangun Jung( @pr0ln ) and Junoh Lee( @bbbig12 ) at Theori( @theori_io ) working with Trend Micro Zero Day Initiative
Alex Birnberg

References

MSRC Advisory MITRE NVD