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CVE Record

CVE-2021-1593: Cisco Packet Tracer for Windows DLL Injection Vulnerability

A vulnerability in Cisco Packet Tracer for Windows could allow an authenticated, local attacker to perform a DLL injection attack on an affected device. 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 inserting a configuration file in a specific path on the system, which can cause a malicious DLL file to be loaded when the application starts. A successful exploit could allow an attacker with normal user privileges to execute arbitrary code on the affected system with the privileges of another user’s account.

HighCVSS 7.3Not KEV-listedUpdated
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

Cisco Packet Tracer for Windows has a local DLL injection flaw. An attacker who already has valid Windows credentials could place a crafted configuration file so Packet Tracer loads a malicious DLL when another user starts it, potentially running code as that user.

Executive priority

Treat this as a high-priority endpoint hygiene issue for environments using Packet Tracer on shared Windows systems. It is not internet-exposed, but it can enable privilege misuse between local users.

Technical view

CVE-2021-1593 is a CWE-427 path handling issue in Cisco Packet Tracer for Windows. The CVSS 3.1 score is 7.3 with local attack vector, low complexity, low privileges, and required user interaction. Successful exploitation can impact confidentiality, integrity, and availability under another user account.

Likely exposure

Exposure is limited to Windows systems running Cisco Packet Tracer, especially shared lab, training, or classroom machines where multiple users log in. The source bundle does not identify exact affected versions.

Exploitation context

The attacker must be local, authenticated, and able to influence a specific runtime path before Packet Tracer starts. The bundle does not indicate known active exploitation, and it is not listed as CISA KEV.

Researcher notes

Evidence supports a local authenticated DLL search/path handling weakness, not remote compromise. Version and fix details are incomplete in the provided bundle, so validation should anchor on Cisco's advisory rather than assumptions.

Mitigation direction

  • Check Cisco's advisory for affected versions, fixed releases, or official workarounds.
  • Remove Packet Tracer from systems where it is not required.
  • Restrict local access to shared Windows systems running Packet Tracer.
  • Use least-privilege accounts on training and lab workstations.
  • Monitor for suspicious DLL loading related to Packet Tracer startup.

Validation and detection

  • Inventory Windows endpoints for Cisco Packet Tracer installations.
  • Compare installed versions with Cisco advisory guidance.
  • Identify shared systems where multiple users run Packet Tracer.
  • Review endpoint telemetry for unexpected DLL loads during Packet Tracer startup.
  • Confirm local user permissions do not allow unnecessary path manipulation.
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.

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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-2021-1593 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
High
CVSS
7.3 (3.1)
Known Exploited
No
Published

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

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
7.3CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H1.35.9Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

7.3High
CVSS 3.1 vector shape for CVE-2021-1593Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

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 Packet Tracern/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.