CVE-2021-21891

Name: CVE-2021-21891
Creator: NVD / NIST
Published: 2021-12-22T19:15:09.437+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.1/10EPSS 2.99%

Last modified Jun 17, 2026

CVE-2021-21891 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. A stack-based buffer overflow vulnerability exists in the Web Manager FsBrowseClean functionality of Lantronix PremierWave 2050 8.9.0.0R4 (in QEMU). A specially crafted HTTP request can lead to remote code execution in the vulnerable portion of the branch (deletefile). EPSS estimates a 2.99% chance of exploitation in the next 30 days.

Description

A stack-based buffer overflow vulnerability exists in the Web Manager FsBrowseClean functionality of Lantronix PremierWave 2050 8.9.0.0R4 (in QEMU). A specially crafted HTTP request can lead to remote code execution in the vulnerable portion of the branch (deletefile). An attacker can make an authenticated HTTP request to trigger this vulnerability.

Metrics

CVSS 3.1

9.1/10

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

EPSS Probability

2.99%

85.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions	Update
Lantronix	Premierwave 2050 Firmware	8.9.0.0	R4

References

https://talosintelligence.com/vulnerability_reports/TALOS-2021-1334Exploit, Technical Description, Third Party Advisory
https://talosintelligence.com/vulnerability_reports/TALOS-2021-1334Exploit, Technical Description, Third Party Advisory

Timeline

Published: Dec 22, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-21891?

How severe is CVE-2021-21891?

CVE-2021-21891 has a CVSS score of 9.1/10 (CRITICAL severity). The EPSS model estimates a 2.99% probability of exploitation in the next 30 days.

How do I fix CVE-2021-21891?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-21891?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST