How severe is CVE-2026-3040?

CVE-2026-3040 has a CVSS 3.x base score of 4.7, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2026-3040 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 9% (95th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-3040?

CVE-2026-3040 affects Draytek Vigor300b Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-3040?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-3040 have an EU (EUVD) identifier?

Yes. CVE-2026-3040 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-7476.

When was CVE-2026-3040 published?

CVE-2026-3040 was published on 2026-02-23 and last updated on 2026-06-17.

CVE-2026-3040

CVE-2026-3040 is a medium-severity vulnerability in Draytek Vigor300b Firmware with a CVSS 3.x base score of 4.7. 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: Medium (CVSS 3.x base score 4.7)
CVSS v2: 5.8
CVSS v4: 2.0
EPSS exploit prediction: 9% (95th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-7476
Weakness: CWE-78
Affected product: Draytek Vigor300b Firmware
Published: 2026-02-23
Last modified: 2026-06-17

Description

A vulnerability was identified in DrayTek Vigor 300B up to 1.5.1.6. This affects the function cgiGetFile of the file /cgi-bin/mainfunction.cgi/uploadlangs of the component Web Management Interface. The manipulation of the argument File leads to os command injection. The attack may be initiated remotely. The exploit is publicly available and might be used. The vendor confirms that "300B is EoL, and this is an authenticated vulnerability. We don't plan to fix it." This vulnerability only affects products that are no longer supported by the maintainer.

Frequently asked questions

What is CVE-2026-3040?: A vulnerability was identified in DrayTek Vigor 300B up to 1.5.1.6. This affects the function cgiGetFile of the file /cgi-bin/mainfunction.cgi/uploadlangs of the component Web Management Interface. The manipulation of the argument File leads to os command injection. The attack may be initiated remotely. The exploit is publicly available and might be used. The vendor confirms that "300B is EoL, and this is an authenticated vulnerability. We don't plan to fix it." This vulnerability only affects products that are no longer supported by the maintainer.
How severe is CVE-2026-3040?: CVE-2026-3040 has a CVSS 3.x base score of 4.7, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2026-3040 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 9% (95th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-3040?: CVE-2026-3040 affects Draytek Vigor300b Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-3040?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-3040 have an EU (EUVD) identifier?: Yes. CVE-2026-3040 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-7476.
When was CVE-2026-3040 published?: CVE-2026-3040 was published on 2026-02-23 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:draytek:vigor300b_firmware:*:*:*:*:*:*:*:*

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