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CVE Record

CVE-2021-1240: Cisco Proximity Desktop for Windows DLL Hijacking Vulnerability

A vulnerability in the loading process of specific DLLs in Cisco Proximity Desktop for Windows could allow an authenticated, local attacker to load a malicious library. To exploit this vulnerability, the attacker must have valid credentials on the Windows system. This vulnerability is due to incorrect handling of directory paths at run time. An attacker could exploit this vulnerability by placing a malicious DLL file in a specific location on the targeted system. This file will execute when the vulnerable application launches. A successful exploit could allow the attacker to execute arbitrary code on the targeted system with the privileges of another user’s account.

MediumCVSS 4.8Not KEV-listedUpdated
Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

Cisco Proximity Desktop for Windows can load a malicious DLL if a logged-in local attacker can place it where the application looks during startup. The result is code execution as another user who launches the application. This is not remotely exploitable based on the supplied sources, but it can support local privilege abuse on shared Windows endpoints.

Executive priority

Treat as a moderate endpoint hardening issue, not an emergency internet-facing incident. Prioritize systems with shared local access or sensitive user accounts. Business urgency increases if Cisco Proximity Desktop remains deployed broadly or on machines used by privileged staff.

Technical view

CVE-2021-1240 is a CWE-427 DLL search path handling flaw in Cisco Proximity Desktop for Windows. CVSS 3.1 is 4.8: local attack vector, low complexity, low privileges required, and user interaction required. Successful exploitation allows arbitrary code execution with another user's account privileges after the vulnerable application launches.

Likely exposure

Exposure appears limited to Windows endpoints running Cisco Proximity Desktop. Risk is higher on shared workstations, VDI, kiosks, or systems where less-trusted authenticated users can sign in locally and write files in locations considered during application DLL loading.

Exploitation context

The source bundle does not show CISA KEV listing or active exploitation. Exploitation requires valid Windows credentials, local access, file placement in a relevant location, and a user launching the vulnerable application. This makes broad internet-scale exploitation unlikely, but insider or post-compromise misuse remains plausible.

Researcher notes

Evidence is limited to the CVE record and Cisco advisory reference in the bundle. No affected version range, patch version, or named workaround is provided here. Validate details against Cisco's advisory before remediation tracking or asset exception decisions.

Mitigation direction

  • Inventory Windows endpoints running Cisco Proximity Desktop.
  • Review Cisco's advisory for supported fixed software or vendor-directed mitigations.
  • Upgrade or remove affected software where Cisco guidance says it is vulnerable.
  • Restrict local logon access on systems using the application.
  • Monitor for unexpected DLL files near application load paths.

Validation and detection

  • Confirm whether Cisco Proximity Desktop is installed on Windows endpoints.
  • Compare installed software status against the Cisco advisory.
  • Check whether shared or low-trust users can access affected systems locally.
  • Review endpoint telemetry for unusual DLL loads around Cisco Proximity launches.
  • Do not mark actively exploited without KEV or credible threat intelligence.
Prepared
Confidence
medium
Sources
3

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-427: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
description · low confidence lookup

Execution behavior lookup

The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2021-1240 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
4.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:L

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
4.8CVSS 3.1MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:L1.33.4Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

4.8Medium
CVSS 3.1 vector shape for CVE-2021-1240Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:L

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
CiscoCisco Proximityn/aListed
Weakness

CWE details

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-427 · source CWE mapping

Uncontrolled Search Path Element

Uncontrolled Search Path Element represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.