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Vulnerability record · CVE-2011-2883 · published 21 July 2011

CVE-2011-2883: Citrix access gateway improper input validation vulnerability

Citrix · Access Gateway

The NSEPA.NsepaCtrl.1 ActiveX control in nsepa.ocx in Citrix Access Gateway Enterprise Edition 8.1 before 8.1-67.7, 9.0 before 9.0-70.5, and 9.1 before 9.1-96.4 attempts to validate signed DLLs by checking the certificate subject, not the signature, which allows man-in-the-middle attackers to execute arbitrary code via HTTP header data referencing a DLL that was signed with a crafted certificate.

9.3 CVSS 2.0 High EPSS 1.5% · top 26.3% CWE-20 · Improper input validation
9.3CVSS 2.0 base score
1.5%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References
16 Jun 2026Last modified by NVD

Description

The NSEPA.NsepaCtrl.1 ActiveX control in nsepa.ocx in Citrix Access Gateway Enterprise Edition 8.1 before 8.1-67.7, 9.0 before 9.0-70.5, and 9.1 before 9.1-96.4 attempts to validate signed DLLs by checking the certificate subject, not the signature, which allows man-in-the-middle attackers to execute arbitrary code via HTTP header data referencing a DLL that was signed with a crafted certificate.

AV:N/AC:M/Au:N/C:C/I:C/A:C

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=928
http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=928

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

10.0CVE-2008-2528Citrix access gateway improper authentication vulnerabilityUnspecified vulnerability in Citrix Access Gateway Standard Edition 4.5.7 and earlier and Advanced Edition 4.5 HF2 and earlier allows attackers to by…EPSS 2.7%9.3CVE-2011-2882Citrix Access Gateway ActiveX control stack buffer overflowThe NSEPA.NsepaCtrl.1 ActiveX control in nsepa.ocx shipped with Citrix Access Gateway Enterprise Edition contains a stack-based buffer overflow (CWE-…EPSS 56%analysed9.3CVE-2010-4566Citrix access gateway vulnerabilityThe web authentication form in the NT4 authentication component in Citrix Access Gateway Enterprise Edition 9.2-49.8 and earlier, and the NTLM authen…EPSS 28%9.3CVE-2007-4013Citrix access gateway vulnerabilityMultiple unspecified vulnerabilities in (1) Net6Helper.DLL (aka Net6Launcher Class) 4.5.2 and earlier, (2) npCtxCAO.dll (aka Citrix Endpoint Analysis…EPSS 4.2%7.6CVE-2007-4017Citrix access gateway vulnerabilityCross-site request forgery (CSRF) vulnerability in the web-based administration console in Citrix Access Gateway before firmware 4.5.5 allows remote …EPSS 2.5%6.8CVE-2007-4016Citrix access gateway vulnerabilityUnspecified vulnerability in the client components in Citrix Access Gateway Standard Edition before 4.5.5 and Advanced Edition before 4.5 HF1 allows …EPSS 2.2%6.8CVE-2007-4018Citrix access gateway vulnerabilityCitrix Access Gateway Advanced Edition before firmware 4.5.5 allows attackers to redirect users to arbitrary web sites and conduct phishing attacks v…EPSS 1.3%6.5CVE-2006-6572Citrix access gateway vulnerabilityUnspecified vulnerability in Citrix Advanced Access Control (AAC) Option 4.0, and Access Gateway 4.2 with Advanced Access Control 4.2, before 2006111…EPSS 1.5%

Source: NIST National Vulnerability Database (record CVE-2011-2883), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.