How severe is CVE-2021-39279?

CVE-2021-39279 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-39279 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-39279?

CVE-2021-39279 primarily affects Moxa Wac-2004 Firmware. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-39279?

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

When was CVE-2021-39279 published?

CVE-2021-39279 was published on 2021-09-07 and last updated on 2026-06-17.

CVE-2021-39279

CVE-2021-39279 is a high-severity vulnerability in Moxa Wac-2004 Firmware with a CVSS 3.x base score of 8.8. 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: High (CVSS 3.x base score 8.8)
CVSS v2: 9.0
EPSS exploit prediction: 5% (91st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-78
Affected product: Moxa Wac-2004 Firmware
Published: 2021-09-07
Last modified: 2026-06-17

Description

Certain MOXA devices allow Authenticated Command Injection via /forms/web_importTFTP. This affects WAC-2004 1.7, WAC-1001 2.1, WAC-1001-T 2.1, OnCell G3470A-LTE-EU 1.7, OnCell G3470A-LTE-EU-T 1.7, TAP-323-EU-CT-T 1.3, TAP-323-US-CT-T 1.3, TAP-323-JP-CT-T 1.3, WDR-3124A-EU 2.3, WDR-3124A-EU-T 2.3, WDR-3124A-US 2.3, and WDR-3124A-US-T 2.3.

Frequently asked questions

What is CVE-2021-39279?: Certain MOXA devices allow Authenticated Command Injection via /forms/web_importTFTP. This affects WAC-2004 1.7, WAC-1001 2.1, WAC-1001-T 2.1, OnCell G3470A-LTE-EU 1.7, OnCell G3470A-LTE-EU-T 1.7, TAP-323-EU-CT-T 1.3, TAP-323-US-CT-T 1.3, TAP-323-JP-CT-T 1.3, WDR-3124A-EU 2.3, WDR-3124A-EU-T 2.3, WDR-3124A-US 2.3, and WDR-3124A-US-T 2.3.
How severe is CVE-2021-39279?: CVE-2021-39279 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-39279 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-39279?: CVE-2021-39279 primarily affects Moxa Wac-2004 Firmware. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-39279?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-39279 published?: CVE-2021-39279 was published on 2021-09-07 and last updated on 2026-06-17.

References

Affected products (12)

cpe:2.3:o:moxa:wac-2004_firmware:1.7:*:*:*:*:*:*:*
cpe:2.3:o:moxa:wac-1001_firmware:2.1:*:*:*:*:*:*:*
cpe:2.3:o:moxa:wac-1001-t_firmware:2.1:*:*:*:*:*:*:*
cpe:2.3:o:moxa:oncell_g3470a-lte-eu_firmware:1.7:*:*:*:*:*:*:*
cpe:2.3:o:moxa:oncell_g3470a-lte-eu-t_firmware:1.7:*:*:*:*:*:*:*
cpe:2.3:o:moxa:tap-323-eu-ct-t_firmware:1.3:*:*:*:*:*:*:*
cpe:2.3:o:moxa:tap-323-us-ct-t_firmware:1.3:*:*:*:*:*:*:*
cpe:2.3:o:moxa:tap-323-jp-ct-t_firmware:1.3:*:*:*:*:*:*:*
cpe:2.3:o:moxa:wdr-3124a-eu_firmware:2.3:*:*:*:*:*:*:*
cpe:2.3:o:moxa:wdr-3124a-eu-t_firmware:2.3:*:*:*:*:*:*:*
cpe:2.3:o:moxa:wdr-3124a-us_firmware:2.3:*:*:*:*:*:*:*
cpe:2.3:o:moxa:wdr-3124a-us-t_firmware:2.3:*:*:*:*:*:*:*

More vulnerabilities in Moxa Wac-2004 Firmware

CVE-2016-8363 — Critical (CVSS 10.0): An issue was discovered in Moxa OnCell OnCellG3470A-LTE, AWK-1131A/3131A/4131A Series, AWK-3191 Series, AWK-5232/6232…
CVE-2016-8362 — Medium (CVSS 6.5): An issue was discovered in Moxa OnCell OnCellG3470A-LTE, AWK-1131A/3131A/4131A Series, AWK-3191 Series, AWK-5232/6232…
CVE-2021-39278 — Medium (CVSS 6.1): Certain MOXA devices allow reflected XSS via the Config Import menu. This affects WAC-2004 1.7, WAC-1001 2.1,…

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