CVE-2021-35034
An insufficient session expiration vulnerability in the CGI program of the Zyxel NBG6604 firmware...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
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.
- Record
CVE-2021-35034- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-613
- Updated
- 2026-11-02
EUVDEUVD-2021-21681
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.
- Record
EUVD-2021-21681- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-38gc-w4h9-7pmf No score
An insufficient session expiration vulnerability in the CGI program of the Zyxel NBG6604 firmware...
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.
- Record
GHSA-38gc-w4h9-7pmf- Weakness
- CWE-613
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2021-35034- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N - 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 - CVSS 2.0
- 6.4 Medium
AV:N/AC:L/Au:N/C:P/I:P/A:N - Weakness
- CWE-613
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-35034 is a high vulnerability (CVSS 7.4) in Zyxel Nbg6604 Firmware, published December 29, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.08%, the 65th percentile. No source names a fixed version.