How severe is CVE-2020-14993?

CVE-2020-14993 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2020-14993 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (92nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-14993?

CVE-2020-14993 primarily affects Draytek Vigor300b Firmware. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-14993?

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-2020-14993 published?

CVE-2020-14993 was published on 2020-06-23 and last updated on 2026-06-17.

CVE-2020-14993

CVE-2020-14993 is a critical-severity vulnerability in Draytek Vigor300b Firmware with a CVSS 3.x base score of 9.8. 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-787.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 5% (92nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Draytek Vigor300b Firmware
Published: 2020-06-23
Last modified: 2026-06-17

Description

A stack-based buffer overflow on DrayTek Vigor2960, Vigor3900, and Vigor300B devices before 1.5.1.1 allows remote attackers to execute arbitrary code via the formuserphonenumber parameter in an authusersms action to mainfunction.cgi.

Frequently asked questions

What is CVE-2020-14993?: A stack-based buffer overflow on DrayTek Vigor2960, Vigor3900, and Vigor300B devices before 1.5.1.1 allows remote attackers to execute arbitrary code via the formuserphonenumber parameter in an authusersms action to mainfunction.cgi.
How severe is CVE-2020-14993?: CVE-2020-14993 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2020-14993 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (92nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-14993?: CVE-2020-14993 primarily affects Draytek Vigor300b Firmware. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-14993?: 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-2020-14993 published?: CVE-2020-14993 was published on 2020-06-23 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:o:draytek:vigor300b_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:draytek:vigor2960_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:draytek:vigor3900_firmware:*:*:*:*:*:*:*:*

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