{"id":"CVE-2011-1271","url":"https://www.cyber-defence.io/tools/cve/CVE-2011-1271","generatedAt":"2026-10-27T23:08:12.435Z","title":"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…","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.\"","published":"2011-05-10T19:55:02.000Z","lastModified":"2026-06-16T23:29:04.000Z","status":"Modified","sourceIdentifier":"secure@microsoft.com","cvss":{"version":"3.1","score":7.7,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L"},"cwe":["CWE-264","CWE-476"],"affected":["microsoft/.net framework"],"epss":{"score":0.20096,"percentile":0.9743,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":1,"verified":true,"firstPublished":"2011-03-04","source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[{"edbId":35740,"kind":"exploit","title":"Microsoft .NET Framework JIT Compiler - Optimization NULL String Remote Code Execution","url":"https://www.exploit-db.com/exploits/35740","sourceUrl":"https://gitlab.com/exploit-database/exploitdb/-/blob/main/exploits/windows/remote/35740.txt","file":"exploits/windows/remote/35740.txt","published":"2011-03-04","added":"2011-03-04","updated":"2015-01-09","author":"Brian Mancini","type":"remote","platform":"windows","port":null,"verified":true,"codes":["CVE-2011-1271","OSVDB-72932"],"tags":null,"aliases":null,"applicationUrl":null,"screenshotUrl":null,"referenceUrl":"https://www.securityfocus.com/bid/47834/info"}]},"verdict":{"level":"urgent","text":"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."},"changes":[],"references":[{"url":"http://stackoverflow.com/questions/2135509/bug-only-occurring-when-compile-optimization-enabled/","tags":["Exploit"],"source":"secure@microsoft.com"},{"url":"https://docs.microsoft.com/en-us/security-updates/securitybulletins/2011/ms11-044","source":"secure@microsoft.com"},{"url":"https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A12686","source":"secure@microsoft.com"},{"url":"http://stackoverflow.com/questions/2135509/bug-only-occurring-when-compile-optimization-enabled/","tags":["Exploit"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://docs.microsoft.com/en-us/security-updates/securitybulletins/2011/ms11-044","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A12686","source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2011-1271","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}