How severe is CVE-2025-7673?

CVE-2025-7673 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-2025-7673 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-7673?

CVE-2025-7673 primarily affects Zyxel Emg3525-t50b Firmware. In total, 26 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2025-7673?

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.

Does CVE-2025-7673 have an EU (EUVD) identifier?

Yes. CVE-2025-7673 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-21579.

When was CVE-2025-7673 published?

CVE-2025-7673 was published on 2025-07-16 and last updated on 2026-06-17.

CVE-2025-7673

CVE-2025-7673 is a critical-severity vulnerability in Zyxel Emg3525-t50b 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-120.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-21579
Weakness: CWE-120
Affected product: Zyxel Emg3525-t50b Firmware
Published: 2025-07-16
Last modified: 2026-06-17

Description

A buffer overflow vulnerability in the URL parser of the zhttpd web server in Zyxel VMG8825-T50K firmware versions prior to V5.50(ABOM.5)C0 could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and potentially execute arbitrary code by sending a specially crafted HTTP request.

Frequently asked questions

What is CVE-2025-7673?: A buffer overflow vulnerability in the URL parser of the zhttpd web server in Zyxel VMG8825-T50K firmware versions prior to V5.50(ABOM.5)C0 could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and potentially execute arbitrary code by sending a specially crafted HTTP request.
How severe is CVE-2025-7673?: CVE-2025-7673 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-2025-7673 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-7673?: CVE-2025-7673 primarily affects Zyxel Emg3525-t50b Firmware. In total, 26 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-7673?: 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.
Does CVE-2025-7673 have an EU (EUVD) identifier?: Yes. CVE-2025-7673 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-21579.
When was CVE-2025-7673 published?: CVE-2025-7673 was published on 2025-07-16 and last updated on 2026-06-17.

References

https://www.zyxel.com/service-provider/global/en/zyxel-security-advisory-remote-code-execution-and-denial-service-vulnerabilities-cpe

Affected products (26)

cpe:2.3:o:zyxel:emg3525-t50b_firmware:*:*:*:*:emea:*:*:*
cpe:2.3:o:zyxel:emg3525-t50b_firmware:*:*:*:*:america:*:*:*
cpe:2.3:o:zyxel:emg5523-t50b_firmware:*:*:*:*:emea:*:*:*
cpe:2.3:o:zyxel:emg5523-t50b_firmware:*:*:*:*:america:*:*:*
cpe:2.3:o:zyxel:emg5723-t50k_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:emg6726-b10a_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:ex3510-b0_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:ex5510-b0_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vmg1312-t20b_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vmg3625-t50b_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vmg3925-b10b_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vmg3925-b10c_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vmg3927-b50a_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vmg3927-b60a_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vmg3927-b50b_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vmg3927-t50k_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vmg4005-b50b_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vmg4927-b50a_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vmg8623-t50b_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vmg8825-b50a_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vmg8825-b60a_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vmg8825-bx0b_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vmg8825-t50k_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:vmg8924-b10d_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:xmg3927-b50a_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:xmg8825-b50a_firmware:*:*:*:*:*:*:*:*

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