CVE-2021-35034

9.1 criticalEPSS 1.1%

Critical (9.1) in zyxel nbg6604 firmware. EPSS 1.1% chance of exploitation in the next 30 days.

An insufficient session expiration vulnerability in the CGI program of the Zyxel NBG6604 firmware could allow a remote attacker to access the device if the correct token can be intercepted.

Severity

CVSS 3.1

9.1 critical

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS: 1.1% chance of exploitation in the next 30 days; higher than 65% of CVEs (scores of 2026-10-31)
CWE: CWE-613
Published: 2021-12-29
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

zyxel:nbg6604_firmware

References

https://www.zyxel.com/support/Zyxel_security_advisory_for_sensitive_information_vulnerabilities_of_NBG6604_home_router.shtml
https://www.zyxel.com/support/Zyxel_security_advisory_for_sensitive_information_vulnerabilities_of_NBG6604_home_router.shtml

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