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Public proof of concept

CVE-2021-1531

A public proof of concept exists; no exploitation attested.

  • Published2021-05-22
  • WeaknessCWE-88

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

A vulnerability in the web UI of Cisco Modeling Labs could allow an authenticated, remote attacker to execute arbitrary commands with the privileges of the web application on the underlying operating system of an affected Cisco Modeling Labs server. This vulnerability is due to insufficient validation of user-supplied input to the web UI. An attacker could exploit this vulnerability by sending a crafted HTTP request to an affected server. A successful exploit could allow the attacker to execute arbitrary commands with the privileges of the web application, virl2, on the underlying operating system of the affected server. To exploit this vulnerability, the attacker must have valid user credentials on the web UI.

Timeline

dates in UTC
  1. 2021-05-2207:15CVE publishedNVD

Versions per branch

NVD
Cisco modeling labs
BranchAffectedFixed in
2.0= 2.0.0no fix published
2.0= 2.0.1no fix published
2.1= 2.1.0no fix published
2.1= 2.1.1no fix published
2.1= 2.1.2no fix published
2.1= 2.1.3no fix published

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

Products declared by the CNA1 product

As cisco, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • Cisco Modeling Labs

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2021-06-23

Fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • CISA-ADPSSVC decisionpoc2024-11-08
  • CNACVSS 3.18.8known since 2026-10-23
  • NVDCVSS 3.18.8read 2026-10-23
  • NVDCVSS 2.09read 2026-10-23
  • CNAweakness (CWE)CWE-88known since 2026-10-23
  • FIRST EPSSEPSS score30.5 %read 2026-11-04
  • GitHub Advisoriesadvisory—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
2021-05-22
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-m74m-f2xh-459p

Frequently asked questions

What is CVE-2021-1531?

A vulnerability in the web UI of Cisco Modeling Labs could allow an authenticated, remote attacker to execute arbitrary commands with the privileges of the web application on the underlying operating system of an affected Cisco Modeling Labs server. This vulnerability is due to insufficient validation of user-supplied input to the web UI. An attacker could exploit this vulnerability by sending a crafted HTTP request to an affected server. A successful exploit could allow the attacker to execute arbitrary commands with the privileges of the web application, virl2, on the underlying operating system of the affected server. To exploit this vulnerability, the attacker must have valid user credentials on the web UI.

Is CVE-2021-1531 actively exploited?

A proof-of-concept exploit exists for CVE-2021-1531, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2021-1531?

CVE-2021-1531 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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