Security readout for executives and security teams
Plain-English summary
A flaw in the Windows installer for Anthropic's Claude Desktop app (versions before 1.1.3363) lets an attacker who can already drop a file into the installer's folder trick the elevated installer into running their malicious code. The result is a local privilege escalation on that Windows machine. It is not remotely exploitable and requires the user to launch the installer.
Executive priority
Low to moderate business urgency. The flaw is local-only, needs user interaction, and is patched by a vendor update. Treat as a routine endpoint hygiene task: ensure Claude Desktop on Windows is updated and remove old installers from shared paths. No emergency response required absent evidence of targeted abuse.
Technical view
Claude Setup.exe is vulnerable to DLL search-order hijacking (CWE-427). After UAC elevation, the installer loads dependencies such as profapi.dll from its own directory before trusted system paths. A planted DLL beside the installer executes with elevated privileges. Anthropic addressed the issue in version 1.1.3363. CVSS 4.0 base score is 4.7 (medium) with vector AV:L/AC:L/PR:L/UI:P, reflecting local access and user interaction requirements.
Likely exposure
Exposure is limited to Windows endpoints where users download and run a pre-1.1.3363 Claude installer, particularly from writable directories like Downloads where an attacker with prior low-privilege foothold can stage a sibling DLL. Servers, macOS, Linux, and already-installed Claude builds are not affected by this installer flaw.
Exploitation context
No public reports of in-the-wild exploitation and not listed in CISA KEV. Exploitation requires an attacker to already have local write access to the installer's directory and the victim to execute the installer with UAC elevation. The advisory was published by Anthropic via their trust portal; no public proof-of-concept is cited in the source bundle.
Researcher notes
Classic CWE-427 search-order hijack in an elevated installer; profapi.dll is a frequently abused proxy DLL because it is delay-loaded by common Windows runtimes. The CVSS 4.0 vector's VC:N/VI:N/VA:N with SC:H/SI:H/SA:H indicates impact scoped to the subsequent system after elevation. Validate by inspecting installer load order with Process Monitor in a lab; do not test against production. Confirm fix in 1.1.3363 hardens DLL search paths (e.g., SetDefaultDllDirectories or absolute paths).
Mitigation direction
- Upgrade Claude for Windows to version 1.1.3363 or later on all endpoints.
- Run installers only from a clean, non-writable location such as a freshly created folder.
- Restrict standard-user write access to shared download or staging directories.
- Block execution of unsigned DLLs from user-writable paths via AppLocker or WDAC policies.
- Follow Anthropic's trust advisory for any additional vendor guidance.
Validation and detection
- Inventory Windows hosts and confirm installed Claude Desktop version is 1.1.3363 or newer.
- Search Downloads and temp folders for legacy Claude Setup.exe binaries below 1.1.3363.
- Audit EDR telemetry for profapi.dll loads originating from user-writable installer directories.
- Verify AppLocker or WDAC rules block DLL loads from non-trusted paths during installer execution.
- Review endpoint logs for UAC elevations of Claude Setup.exe in the affected window.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-427: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-22561 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 4.7 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H——hackeroneVulnerability scoring details
Base CVSS 4.0 score
4.7MediumVector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Uncontrolled Search Path Element
Uncontrolled Search Path Element represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.