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CVE-2011-2882· NVD / CVE Program· CNA mitre

Stack-based buffer overflow in the NSEPA.NsepaCtrl.1 ActiveX control in nsepa.ocx in Citrix Access Gateway Enterprise Edition 8.1 before 8.1

Stack-based buffer overflow in 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 allows remote attackers to execute arbitrary code via crafted HTTP header data.

CriticalCVSS 9.3 · v2.0—Weaponized No fix recorded
Published
Jul 21, 2011
Updated
Jun 16, 2026
EPSS
56.4% · 99th percentile
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Report tools

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Action score

54

Plan

Add it to your regular patch cycle.

CVSS
37 / 40 · 9.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
17 / 30 · 56.4%

Affected systems

VendorProduct
citrixaccess gateway

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • citrix access gateway8.1
  • citrix access gateway9.0
  • citrix access gateway9.1

Same product

citrix: all records

Other highest-scoring records for the same primary product.

  • CVE-2010-4566The web authentication form in the NT4 authentication component in Citrix Access Gateway Enterprise Edition 9.2-49.8 and earlier, and the NT
    45Plan
  • CVE-2008-2528Unspecified vulnerability in Citrix Access Gateway Standard Edition 4.5.7 and earlier and Advanced Edition 4.5 HF2 and earlier allows attack
    41Plan
  • CVE-2007-4013Multiple unspecified vulnerabilities in (1) Net6Helper.DLL (aka Net6Launcher Class) 4.5.2 and earlier, (2) npCtxCAO.dll (aka Citrix Endpoint
    38Monitor
  • CVE-2011-2883The 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
    37Monitor
  • CVE-2007-4017Cross-site request forgery (CSRF) vulnerability in the web-based administration console in Citrix Access Gateway before firmware 4.5.5 allow
    31Monitor
  • CVE-2007-4016Unspecified vulnerability in the client components in Citrix Access Gateway Standard Edition before 4.5.5 and Advanced Edition before 4.5 HF
    28Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

  • Metasploit module ×1
  • Exploit-DB entry ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Exploit-DB entryremote2011-08-31
Metasploit moduleexploit/windows/browser/citrix_gateway_actxCitrix Gateway ActiveX Control Stack Based Buffer Overflow Vulnerabilityexploit2011-07-14

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Metasploit-8 d
  2. Published
  3. First PoC+40 d
  4. TodaySep 30, 2026+5550 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Technical details

Attack conditions

    If successful

    Confidentiality
    C · data can be read
    Integrity
    C · data or configuration can be modified
    Availability
    C · the service can be disrupted
    Attack complexity
    M
    Confidentiality impact
    C
    Integrity impact
    C
    Availability impact
    C

    Weakness class (CWE)

    CWE-119 · Improper Restriction of Operations within the Bounds of a Memory Buffer

    CVSS vector

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

    nvd-primary

    Attack context

    MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

    ATT&CK techniques

    —

    Noroxi analysis

    No Noroxi analysis for this record yet

    We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

    We use this product, ask for help

    Change log

    No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

    References

    Vendor advisories and official records. Exploit/PoC links are deliberately left out.

    All records