How severe is CVE-2020-25014?

CVE-2020-25014 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-2020-25014 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-25014?

CVE-2020-25014 primarily affects Zyxel Zld. In total, 11 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-25014?

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-2020-25014 published?

CVE-2020-25014 was published on 2020-11-27 and last updated on 2026-06-17.

CVE-2020-25014

CVE-2020-25014 is a critical-severity vulnerability in Zyxel Zld 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: 4% (90th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Zyxel Zld
Published: 2020-11-27
Last modified: 2026-06-17

Description

A stack-based buffer overflow in fbwifi_continue.cgi on Zyxel UTM and VPN series of gateways running firmware version V4.30 through to V4.55 allows remote unauthenticated attackers to execute arbitrary code via a crafted http packet.

Frequently asked questions

What is CVE-2020-25014?: A stack-based buffer overflow in fbwifi_continue.cgi on Zyxel UTM and VPN series of gateways running firmware version V4.30 through to V4.55 allows remote unauthenticated attackers to execute arbitrary code via a crafted http packet.
How severe is CVE-2020-25014?: CVE-2020-25014 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-2020-25014 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-25014?: CVE-2020-25014 primarily affects Zyxel Zld. In total, 11 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-25014?: 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-2020-25014 published?: CVE-2020-25014 was published on 2020-11-27 and last updated on 2026-06-17.

References

Affected products (11)

cpe:2.3:o:zyxel:zld:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:access_points_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:access_points_firmware:6.10:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:access_points_firmware:6.10:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:access_points_firmware:6.10:patch2:*:*:*:*:*:*
cpe:2.3:o:zyxel:access_points_firmware:6.10:patch3:*:*:*:*:*:*
cpe:2.3:o:zyxel:access_points_firmware:6.10:patch4:*:*:*:*:*:*
cpe:2.3:o:zyxel:access_points_firmware:6.10:patch5:*:*:*:*:*:*
cpe:2.3:o:zyxel:access_points_firmware:6.10:patch6:*:*:*:*:*:*
cpe:2.3:o:zyxel:access_points_firmware:6.10:patch7:*:*:*:*:*:*
cpe:2.3:o:zyxel:access_points_firmware:-:*:*:*:*:*:*:*

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