CVE-2015-2479
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 · uneditedThe RyuJIT compiler in Microsoft .NET Framework 4.6 produces incorrect code during an attempt at optimization, which allows remote attackers to execute arbitrary code via a crafted .NET application, aka "RyuJIT Optimization Elevation of Privilege Vulnerability," a different vulnerability than CVE-2015-2480 and CVE-2015-2481.
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 RyuJIT just-in-time compiler in Microsoft .NET Framework 4.6 generates incorrect machine code during optimization passes, allowing attackers to achieve arbitrary code execution by supplying specially crafted .NET applications.
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 data= 4.6CVSS 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.
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Identify installed .NET Framework versionCheck the Windows registry key HKLM\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full for the Version value under the Release key, or use the command 'reg query "HKLM\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full" /v Version'Affected if The version reported is 4.6.0 or starts with 4.6, indicating .NET Framework 4.6 is installed
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Confirm RyuJIT component presenceCheck for the presence of the RyuJIT compiler files in the .NET Framework directory, typically found at %WINDIR%\Microsoft.NET\Framework\v4.0.30319 or the 64-bit equivalent, or verify mscorjit.dll exists in the .NET Framework installation directoryAffected if The RyuJIT compiler (mscorjit.dll) is present in a .NET 4.6 installation, indicating the vulnerable component is present
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Check for MS15-080 security updateVerify if the MS15-080 security update has been applied by checking the registry key HKLM\SOFTWARE\Microsoft\Updates\UpdateId for MS15-080, or use the command 'wmic qfe list | findstr "MS15-080"' to list installed hotfixesAffected if The MS15-080 update is NOT installed, meaning the original vulnerable RyuJIT compiler version remains in place
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Verify file version of JIT compilerCheck the file version of mscorjit.dll in the .NET Framework directory. Right-click the file, select Properties, and examine the File Version field under the Details tabAffected if The file version is the original release version shipped with .NET 4.6 and has not been updated to the patched version from MS15-080
A system is affected if .NET Framework 4.6 is installed without the MS15-080 security update, as the original RyuJIT compiler remains present and vulnerable to code execution attacks.
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.
From vendor dataApply the Microsoft security update for .NET Framework 4.6 (MS15-080) to replace the vulnerable RyuJIT compiler with the corrected version.
- Consultation4.0 h
- Implementation4.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,504.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2015-2479 — 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-2015-2479 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
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- 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
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