OnlyPatch
Application Information Services

CVE-2026-61357 — Application Information Services Elevation of Privilege Vulnerability

Important CVSS 7.8 EPSS 0.00311 🔬 Patch diffed 2026-08 archive

Executive Summary

Use after free in Application Information Services 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-416: Use After Free
Released Aug 11 2026
Last Updated Aug 11 2026
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.00311 — 0.23682 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

0.00311
probability of exploitation in the next 30 days
0.23682 percentile - updated 2026-08-14
View on FIRST.org

Affected Products

2 affected products
Product KB Article Severity Impact Restart Required
Windows 11 Version 24H2 for ARM64-based Systems 5120994 (Security Hotpatch Update) 5121003 (Security Update) Important Elevation of Privilege 5101650 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 10.0.26100.9106 10.0.26100.9168 Yes None Windows 11 Version 24H2 for x64-based Systems 5121003 (Security Update) 5120994 (Security Hotpatch Update) Important Elevation of Privilege 5101650 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 10.0.26100.9168 10.0.26000.9106 Yes None Windows 11 Version 25H2 for ARM64-based Systems 5121003 (Security Update) 5120994 (Security Hotpatch Update) Important Elevation of Privilege 5101650 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 10.0.26200.9168 10.0.26100.9106 Yes None Windows 11 Version 25H2 for x64-based Systems 5121003 (Security Update) 5120994 (Security Hotpatch Update) Important Elevation of Privilege 5101650 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 10.0.26200.9168 10.0.26100.9106 Yes None Windows 11 Version 26H1 for ARM64-based Systems 5121000 (Security Update) Important Elevation of Privilege Yes
Windows 11 version 26H1 for x64-based Systems 5121000 (Security Update) Important Elevation of Privilege Yes

Patches

1 patch
Article Type Restart
5121000 Security Update Yes

Patch Diff

ghidriff · appinfo.dll (KB5121003)

Use-after-free (CWE-416) in the Windows Application Information Service (AppInfo / UAC elevation broker) appinfo.dll RAiLaunchAdminProcess, local EoP to SYSTEM. RAiLaunchAdminProcess is the RPC method a client invokes to request launch of an elevated (admin) process (the AppInfo interface behind ShellExecute 'runas' / consent). It impersonates the calling client (RpcImpersonateClient), builds several heap-allocated request strings/parameters (application path, parameters, etc.; LocalFree-owned WCHAR buffers), and drives the elevated launch, reverting impersonation (RpcRevertToSelf) around the sensitive steps. PRE: one of these heap allocations was freed but a stale pointer to it was still used on a later step / error path (a use-after-free of a LocalFree'd buffer), reachable by an unprivileged local caller of the AppInfo RPC and, because AppInfo runs as SYSTEM and performs the launch, exploitable for local EoP to SYSTEM. Diff of appinfo.dll 10.0.26100.8972 -> .9168 (Aug 11 2026, KB5121003) confirms the fix: gated behind CFR flag Feature_1715195192, RAiLaunchAdminProcess is reworked to manage the affected string via a wil::unique_any_t RAII wrapper (make_unique_string_nothrow with a LocalFree resource policy; assignment/reset/scoped-destruction), binding the buffer's lifetime so it is freed exactly once and cannot be referenced after free, and the RpcImpersonateClient/RpcRevertToSelf sequence around it is restructured. Note: RAiLaunchAdminProcess is confirmed code-changed under Feature_1715195192 with the new RAII string guard; the exact freed local is not cleanly isolable in this large refactor, so the precise freed buffer is stated at confirmed-changed level and the mechanism follows the CWE-416 classification and the RAII-guard evidence.

Pre-patch version 10.0.26100.8972 Download
Post-patch version 10.0.26100.9168 Download
Function Address Change Note
RAiLaunchAdminProcess code change code (affected buffer now RAII-managed; impersonation flow restructured, CFR-gated) Pre: a LocalFree-owned WCHAR request buffer was freed but a stale pointer was still used on a later/error path -> UAF, reachable by the unprivileged AppInfo RPC client. Post (Feature_1715195192): the buffer is held in wil::unique_any_t<...LocalFree...> (make_unique_string_nothrow / operator= / reset), so it is freed once and never used after free; RpcImpersonateClient/RpcRevertToSelf ordering reworked.
LUATelemetry::LaunchAdminProcess code change code (telemetry helper extracted/updated) Templated telemetry helper around the admin-launch path, updated alongside RAiLaunchAdminProcess under the same gate.
Feature_1715195192 gate added (CFR gate) CFR flag gating the RAII-managed lifetime fix; the original use-after-free path still ships when disabled.
View full diff report View RCA report

Attack Path

An unprivileged client's elevation RPC frees a request buffer that AppInfo then uses after free, in the SYSTEM elevation broker

Attack path for CVE-2026-61357 An unprivileged client's elevation RPC frees a request buffer that AppInfo then uses after free, in the SYSTEM elevation broker 01 — ENTRY Local user calls the AppInfo RPC RAiLaunchAdminProcess to request an elevated launch appinfo.dll runs in the SYSTEM Application Information Service; the method is reachable by an unprivileged caller (the 'runas'/consent path). AV:L/PR:L/AC:L. 02 — CONTROLLED INPUT Supplies request parameters that drive the heap-string handling in the launch path RAiLaunchAdminProcess impersonates the client and builds LocalFree-owned WCHAR buffers for the request. 03 — MISSING CHECK A request buffer is freed but a stale pointer is still used later (CWE-416) The freed LocalFree buffer is referenced on a subsequent step / error path -> use-after-free in the SYSTEM service. 04 — PATH Reused freed allocation lets the attacker influence SYSTEM-side state AppInfo performs the privileged launch, so controlling the freed/reused memory is an EoP primitive. 05 — PRIMITIVE Use-after-free in the SYSTEM elevation broker -> EoP to SYSTEM The Aug 2026 fix (Feature_1715195192) binds the buffer to a wil::unique_any_t RAII guard so it cannot be used after free.

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.

Exploits & PoC

Detection Rules

Acknowledgments

Brandon Fisher
Pwnforr777

On This Page