CVE-2011-1271
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…
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 20.1%, higher than 97% of all known CVEs. Patch or mitigate before the next change window.
Description
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."
- CVSS 3.1
- 7.7 HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
- EPSS
- 20.10% probability · 97th percentile
- Public exploits
- 1 in Exploit-DB · verified · first 4 March 2011
- CISA KEV
- Not listed
- Weakness
- CWE-264, CWE-476
- Affected
- microsoft/.net framework
- Source
- secure@microsoft.com
EPSS 20.1% since 26 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
Public exploits (1)
Entries in Exploit-DB that cite this CVE. Links go to the Exploit-DB page and to the file in the public repository; nothing is hosted here. A verified tick means the Exploit-DB team confirmed the exploit works against the stated version.
References
- http://stackoverflow.com/questions/2135509/bug-only-occurring-when-compile-optimization-enabled/Exploit
- https://docs.microsoft.com/en-us/security-updates/securitybulletins/2011/ms11-044
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A12686
- http://stackoverflow.com/questions/2135509/bug-only-occurring-when-compile-optimization-enabled/Exploit
- https://docs.microsoft.com/en-us/security-updates/securitybulletins/2011/ms11-044
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A12686
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.