CVE-2011-1247
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedUntrusted search path vulnerability in the Microsoft Active Accessibility component in Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2, R2, and R2 SP1, and Windows 7 Gold and SP1 allows local users to gain privileges via a Trojan horse DLL in the current working directory, aka "Active Accessibility Insecure Library Loading Vulnerability."
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe Microsoft Active Accessibility component has an untrusted search path vulnerability (DLL preloading/hijacking) where it loads DLLs from the current working directory without proper path validation, allowing local attackers to place a malicious DLL that gets executed with elevated privileges.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE dataall versionsall versionsall versionsall versions= r2all versionsall versionsCVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- M
- Authentication
- None
- Confidentiality
- Complete
- Integrity
- Complete
- Availability
- Complete
AV:N/AC:M/Au:N/C:C/I:C/A:C
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
-
Verify Microsoft Active Accessibility component is installedOpen Programs and Features (appwiz.cpl) or check the registry at HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components for entries related to Active Accessibility, or check for the presence of oa300.dll or other MSAA DLLs in system directoriesAffected if The Microsoft Active Accessibility component (oa300.dll or related) is present on the system without the KB2476687 security update applied
-
Check if security update KB2476687 is installedRun 'wmic qfe get hotfixid,installedon' or check Add/Remove Programs view for security update KB2476687, or query the registry at HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Component Based Servicing\Packages for the update packageAffected if The security update KB2476687 is NOT listed among installed hotfixes, meaning the DLL preloading vulnerability remains unpatched
-
Identify processes that load the vulnerable Active Accessibility DLLUse Process Explorer or run 'tasklist /m' to list DLLs loaded by processes, or check for processes using oa300.dll specifically - common spawn points include applications launched from directories where users can write filesAffected if Processes such as explorer's help center, assistive technology helpers, or accessibility-aware applications are running with oa300.dll loaded and KB2476687 is absent
-
Audit directories where applications are launched for suspicious DLLsCheck directories that are commonly the current working directory when launching applications (especially shared/network directories, download folders, or user-writable locations) for unexpected DLL files with names matching Active Accessibility components (oa300.dll, acccheck.dll, etc.)Affected if Unexpected DLLs matching the Active Accessibility component names are found in directories from which applications are commonly launched, indicating potential DLL hijacking attempt
-
Verify the version of the vulnerable DLL fileCheck the file version of oa300.dll in the system32 folder by right-clicking the file, selecting Properties, and viewing the File Version tab - compare against the patched version delivered by KB2476687Affected if The oa300.dll version is older than the patched version associated with KB2476687, or the file exists without corresponding patch installation
A system is affected if Microsoft Active Accessibility component is present and security update KB2476687 has not been installed, allowing DLL preloading attacks when applications are launched from writable directories.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedApply Microsoft security update KB2476687 to affected systems and ensure users do not have write access to directories from which applications may be launched (particularly shared/network directories).
Windows 10/11 (workstations) or Windows Server 2016+ (servers)
- Identify all systems running affected Windows versions (XP, Vista, 2003, 2008, 2008 R2, 7) within the environment
- Backup all critical data and system configurations
- Upgrade affected workstations to a supported Windows version (Windows 10 or Windows 11)
- Upgrade affected servers to a supported Windows Server version (Windows Server 2016 or later)
- After upgrade, apply all available Windows Updates and security patches
- Verify the Active Accessibility component is no longer vulnerable to DLL hijacking
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,880.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2011-1247 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2011-1247 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data