CVE-2021-21891Public exploitNetwork attack vector

Authenticated code execution via unchecked path formatting

Published Dec 22, 2021 · Updated Aug 3, 2024

Stack-based buffer overflow in Lantronix PremierWave 2050 8.9.0.0R4 allows remote authenticated users to execute code via HTTP. The FsBrowseClean deletefile branch concatenates a user-controlled path into a 4,120-byte stack buffer with sprintf without checking its length. A user with filesystem permission can overwrite the stack frame and control the program counter, enabling code execution in ltrx_evo.

CVSS severity9.1
Critical
EPSS probability2.99%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Stack-based buffer overflow in Lantronix PremierWave 2050 8.9.0.0R4 allows remote authenticated users to execute code via HTTP. The FsBrowseClean deletefile branch concatenates a user-controlled path into a 4,120-byte stack buffer with sprintf without checking its length. A user with filesystem permission can overwrite the stack frame and control the program counter, enabling code execution in ltrx_evo.

The record

CVE
CVE-2021-21891
Published
Dec 22, 2021
Updated
Aug 3, 2024
Vendor
Lantronix
Product
PremierWave 2050
Classifications
CWE-121, CWE-787, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 22, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Lantronix PremierWave 2050 8.9.0.0R4 (in QEMU)

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Lantronix · PremierWave 2050version=Lantronix PremierWave 2050 8.9.0.0R4 (in QEMU)

Published CVSS scores

9.1Cisco TalosCVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
9.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
6.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
CWE-787Out-of-bounds Write
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo