CVE-2021-35029
An authentication bypasss vulnerability in the web-based management interface of Zyxel USG/Zywall...
An authentication bypasss vulnerability in the web-based management interface of Zyxel USG/Zywall series firmware versions 4.35 through 4.64 and USG Flex, ATP, and VPN series firmware versions 4.35 through 5.01, which could allow a remote attacker to execute arbitrary commands on an affected device.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
An authentication bypasss vulnerability in the web-based management interface of Zyxel USG/Zywall series firmware versions 4.35 through 4.64 and USG Flex, ATP, and VPN series firmware versions 4.35 through 5.01, which could allow a remote attacker to execute arbitrary commands on an affected device.
- Record
CVE-2021-35029- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-287
- Updated
- 2026-11-02
EUVDEUVD-2021-21676
An authentication bypasss vulnerability in the web-based management interface of Zyxel USG/Zywall series firmware versions 4.35 through 4.64 and USG Flex, ATP, and VPN series firmware versions 4.35 through 5.01, which could allow a remote attacker to execute arbitrary commands on an affected device.
- Record
EUVD-2021-21676- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-2h44-x2fr-537p No score
An authentication bypasss vulnerability in the web-based management interface of Zyxel USG/Zywall...
An authentication bypasss vulnerability in the web-based management interface of Zyxel USG/Zywall series firmware versions 4.35 through 4.64 and USG Flex, ATP, and VPN series firmware versions 4.35 through 5.01, which could allow a remote attacker to execute arbitrary commands on an affected device.
- Record
GHSA-2h44-x2fr-537p- Weakness
- CWE-287
- Updated
- 2026-11-02
NVD
An authentication bypasss vulnerability in the web-based management interface of Zyxel USG/Zywall series firmware versions 4.35 through 4.64 and USG Flex, ATP, and VPN series firmware versions 4.35 through 5.01, which could allow a remote attacker to execute arbitrary commands on an affected device.
- Record
CVE-2021-35029- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 7.5 High
AV:N/AC:L/Au:N/C:P/I:P/A:P - Weakness
- CWE-287
- Updated
- 2026-11-02
Affected products
- zyxel usg/zywall series firmware
- zyxel vpn series firmware
- zyxel atp series firmware
- zyxel usg flex series firmware
- zyxel usg1000 firmware
- zyxel usg100 firmware
- zyxel usg1100 firmware
- zyxel usg110 firmware
- zyxel usg1900 firmware
- zyxel usg20-vpn firmware
- zyxel usg2000 firmware
- zyxel usg200 firmware
Show 29 moreShow less
- zyxel usg20 firmware
- zyxel usg20w-vpn firmware
- zyxel usg20w firmware
- zyxel usg210 firmware
- zyxel usg2200-vpn firmware
- zyxel usg300 firmware
- zyxel usg310 firmware
- zyxel usg40 firmware
- zyxel usg40w firmware
- zyxel usg50 firmware
- zyxel usg60 firmware
- zyxel usg60w firmware
- zyxel usg flex 100 firmware
- zyxel usg flex 100w firmware
- zyxel usg flex 200 firmware
- zyxel usg flex 500 firmware
- zyxel usg flex 700 firmware
- zyxel zywall 1100 firmware
- zyxel zywall 110 firmware
- zyxel zywall 310 firmware
- zyxel zywall atp100 firmware
- zyxel zywall atp100w firmware
- zyxel zywall atp200 firmware
- zyxel zywall atp500 firmware
- zyxel zywall atp700 firmware
- zyxel zywall atp800 firmware
- zyxel zywall vpn100 firmware
- zyxel zywall vpn300 firmware
- zyxel zywall vpn50 firmware
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-2021-35029 is a critical vulnerability (CVSS 9.8) in Zyxel Usg/zywall Series Firmware, published July 2, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.25%, the 83rd percentile. No source names a fixed version.