The JIT compiler in Microsoft .NET Framework 3.5 Gold and SP1, 3.5.1, and 4.0, when…
Priority MEDIUM 54CWE-476Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Impact type
- Denial of service, Security bypass
- Confidentiality · integrity · availability
- High · High · Low
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-476 and CWE-264.
Summary
The JIT compiler in Microsoft .NET Framework 3.5 Gold and SP1, 3.5.1, and 4.0, when IsJITOptimizerDisabled is false, does not properly handle expressions related to null strings, which allows context-dependent attackers to bypass intended access restrictions, and consequently execute arbitrary code, in opportunistic circumstances by leveraging a crafted application, as demonstrated by (1) a crafted XAML browser application (aka XBAP), (2) a crafted ASP.NET application, or (3) a crafted .NET Framework application, aka ".NET Framework JIT Optimization Vulnerability."
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.20096 97th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 23
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:microsoft:.net_framework:4.0:*:*:*:*:*:*:* | 4.0 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_2003_server:*:sp2:*:*:*:*:*:* | all versions | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_7:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_7:-:sp1:x86:*:*:*:*:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2003:*:sp2:*:*:*:*:*:* | all versions | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2008:*:*:itanium:*:*:*:*:* | all versions | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2008:*:*:x32:*:*:*:*:* | all versions | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2008:*:*:x64:*:*:*:*:* | all versions | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2008:*:sp2:x32:*:*:*:*:* | all versions | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2008:*:sp2:x64:*:*:*:*:* | all versions | Running on | Microsoft |
- cpe:2.3:a:microsoft:.net_framework:4.0:*:*:*:*:*:*:* Versions 4.0 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_2003_server:*:sp2:*:*:*:*:*:* Versions all versions Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_7:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_7:-:sp1:x86:*:*:*:*:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2003:*:sp2:*:*:*:*:*:* Versions all versions Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2008:*:*:itanium:*:*:*:*:* Versions all versions Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2008:*:*:x32:*:*:*:*:* Versions all versions Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2008:*:*:x64:*:*:*:*:* Versions all versions Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2008:*:sp2:x32:*:*:*:*:* Versions all versions Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2008:*:sp2:x64:*:*:*:*:* Versions all versions Running on ·Microsoft
Show 13 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:microsoft:windows_server_2008:-:sp2:itanium:*:*:*:*:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2008:r2:*:itanium:*:*:*:*:* | r2 | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2008:r2:*:x64:*:*:*:*:* | r2 | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_vista:*:sp1:*:*:*:*:*:* | all versions | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_vista:*:sp2:*:*:*:*:*:* | all versions | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_xp:*:sp3:*:*:*:*:*:* | all versions | Running on | Microsoft |
| cpe:2.3:o:microsoft:windows_xp:-:sp2:x64:*:*:*:*:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:a:microsoft:.net_framework:3.5.1:*:*:*:*:*:*:* | 3.5.1 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_7:-:sp1:x64:*:*:*:*:* | not specified by NVD | Running on | Microsoft |
| cpe:2.3:a:microsoft:.net_framework:2.0:sp2:*:*:*:*:*:* | 2.0 sp2 | Vulnerable | Microsoft |
| cpe:2.3:a:microsoft:.net_framework:3.5:sp1:*:*:*:*:*:* | 3.5 sp1 | Vulnerable | Microsoft |
| cpe:2.3:a:microsoft:.net_framework:2.0:sp1:*:*:*:*:*:* | 2.0 sp1 | Vulnerable | Microsoft |
| cpe:2.3:a:microsoft:.net_framework:3.5:*:*:*:*:*:*:* | 3.5 | Vulnerable | Microsoft |
- cpe:2.3:o:microsoft:windows_server_2008:-:sp2:itanium:*:*:*:*:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2008:r2:*:itanium:*:*:*:*:* Versions r2 Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2008:r2:*:x64:*:*:*:*:* Versions r2 Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_vista:*:sp1:*:*:*:*:*:* Versions all versions Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_vista:*:sp2:*:*:*:*:*:* Versions all versions Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_xp:*:sp3:*:*:*:*:*:* Versions all versions Running on ·Microsoft
- cpe:2.3:o:microsoft:windows_xp:-:sp2:x64:*:*:*:*:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:a:microsoft:.net_framework:3.5.1:*:*:*:*:*:*:* Versions 3.5.1 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_7:-:sp1:x64:*:*:*:*:* Versions not specified by NVD Running on ·Microsoft
- cpe:2.3:a:microsoft:.net_framework:2.0:sp2:*:*:*:*:*:* Versions 2.0 sp2 Vulnerable ·Microsoft
- cpe:2.3:a:microsoft:.net_framework:3.5:sp1:*:*:*:*:*:* Versions 3.5 sp1 Vulnerable ·Microsoft
- cpe:2.3:a:microsoft:.net_framework:2.0:sp1:*:*:*:*:*:* Versions 2.0 sp1 Vulnerable ·Microsoft
- cpe:2.3:a:microsoft:.net_framework:3.5:*:*:*:*:*:*:* Versions 3.5 Vulnerable ·Microsoft
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2011-1271
- 2026-10-03 Alias added: GHSA-w649-2qr9-fg6v
References
More Microsoft .net Framework vulnerabilities
- TI-2020-00622 XML injection in Microsoft .NET Framework 4.6/4.6.1/4.6.2/4.7/4.7.1/4.7.2 KEVCVSS 3.1CRITICAL 9.8
- TI-2020-01112 A remote code execution vulnerability exists in .NET Framework, Microsoft SharePoint, and… KEVCVSS 3.1HIGH 7.8
- TI-2017-06273 Code injection in Microsoft .NET Framework KEVCVSS 3.1HIGH 7.8
- TI-2015-01495 The Windows DirectWrite library, as used in Microsoft .NET Framework 3.0 SP2, 3.5, 3.5.1… KEVCVSS 3.1HIGH 7.8
- TI-2024-19239 .NET Framework Information Disclosure Vulnerability KEVCVSS 3.1HIGH 7.5
- TI-2023-18684 ASP.NET Elevation of Privilege Vulnerability CVSS 3.1HIGH 8.8
Sources
- CVE-2011-1271 · CVE Program
- CVE-2011-1271 · NVD
- FIRST EPSS
- GHSA-w649-2qr9-fg6v · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences