How severe is CVE-2021-21877?

CVE-2021-21877 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-21877 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (84th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21877?

CVE-2021-21877 affects Lantronix Premierwave 2050 Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-21877?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-21877 published?

CVE-2021-21877 was published on 2021-12-22 and last updated on 2026-06-17.

CVE-2021-21877

CVE-2021-21877 is a critical-severity vulnerability in Lantronix Premierwave 2050 Firmware with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-78.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v2: 6.5
EPSS exploit prediction: 3% (84th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-78
Affected product: Lantronix Premierwave 2050 Firmware
Published: 2021-12-22
Last modified: 2026-06-17

Description

Specially-crafted HTTP requests can lead to arbitrary command execution in “GET” requests. An attacker can make authenticated HTTP requests to trigger this vulnerability.

Frequently asked questions

What is CVE-2021-21877?: Specially-crafted HTTP requests can lead to arbitrary command execution in “GET” requests. An attacker can make authenticated HTTP requests to trigger this vulnerability.
How severe is CVE-2021-21877?: CVE-2021-21877 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-21877 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (84th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21877?: CVE-2021-21877 affects Lantronix Premierwave 2050 Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-21877?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-21877 published?: CVE-2021-21877 was published on 2021-12-22 and last updated on 2026-06-17.

References

https://talosintelligence.com/vulnerability_reports/TALOS-2021-1315

Affected products (1)

cpe:2.3:o:lantronix:premierwave_2050_firmware:8.9.0.0:r4:*:*:*:*:*:*

More vulnerabilities in Lantronix Premierwave 2050 Firmware

CVE-2021-21892 — Critical (CVSS 9.9): A stack-based buffer overflow vulnerability exists in the Web Manager FsUnmount functionality of Lantronix PremierWave…
CVE-2021-21889 — Critical (CVSS 9.9): A stack-based buffer overflow vulnerability exists in the Web Manager Ping functionality of Lantronix PremierWave 2050…
CVE-2021-21883 — Critical (CVSS 9.9): An OS command injection vulnerability exists in the Web Manager Diagnostics: Ping functionality of Lantronix…
CVE-2021-21881 — Critical (CVSS 9.9): An OS command injection vulnerability exists in the Web Manager Wireless Network Scanner functionality of Lantronix…
CVE-2021-21872 — Critical (CVSS 9.9): An OS command injection vulnerability exists in the Web Manager Diagnostics: Traceroute functionality of Lantronix…
CVE-2021-21894 — Critical (CVSS 9.1): A directory traversal vulnerability exists in the Web Manager FsTFtp functionality of Lantronix PremierWave 2050…

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