No exploitation reported

CVE-2011-1271

No exploitation reported by the sources we read.

Published2011-05-10
WeaknessCWE-264 · CWE-476

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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."

Timeline

dates in UTC

2011-05-1019:55CVE publishedNVD
2026-10-2319:23EPSS crossed 10 %FIRST EPSS

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2011-1271?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2011-1271?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · CISA-ADP

Microsoft .net frameworkversion to verify

Branch	Affected	Fixed in	Source
4.0	= 4.0	no fix published	NVD
3.5	= 3.5.1	no fix published	NVD
2.0	= 2.0	no fix published	NVD
3.5	= 3.5	no fix published	NVD
3.5	= 3.5 Gold	no fix published	CISA-ADP

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionnone2024-01-10
OpenCVESSVC decisionnone—
CISA-ADPCVSS 3.17.72024-10-17
NVDCVSS 2.05.1read 2026-10-23
CISA-ADPweakness (CWE)CWE-4762024-10-17
NVDweakness (CWE)CWE-264read 2026-10-23
FIRST EPSSEPSS score20.1 %read 2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
Published: 2011-05-10
Last Modified: 2026-06-16
NVD status: Modified

Frequently asked questions

What is CVE-2011-1271?

Is CVE-2011-1271 actively exploited?

Active exploitation of CVE-2011-1271 has not been confirmed. Its EPSS score was 20.1% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2011-1271?

CVE-2011-1271 has a CVSS v3 base score of 7.7 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L.

Hear about the next vulnerability in your software

Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

Get alerts for this product CISA KEV additions, October 2026 Search CVEs

No credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
Running this software? Vulnerability monitoring alerts you to new vulnerabilities in your products.

Related vulnerabilities

Same product first, then the same vendor advisory and the same publication week.

Back to CVE Database