CVE-2021-35034

CVE-2021-35034 is a high-severity vulnerability in Zyxel Nbg6604 Firmware with a CVSS 3.x base score of 7.4. 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-613.

Key facts

Description

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.

Frequently asked questions

What is CVE-2021-35034?
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.
How severe is CVE-2021-35034?
CVE-2021-35034 has a CVSS 3.x base score of 7.4, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2021-35034 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-35034?
CVE-2021-35034 affects Zyxel Nbg6604 Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-35034?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-35034 published?
CVE-2021-35034 was published on 2021-12-29 and last updated on 2026-06-17.

References

Affected products (1)

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