CVE-2021-3297
On Zyxel NBG2105 V1.00(AAGU.2)C0 devices, setting the login cookie to 1 provides administrator access.
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 20.5%, higher than 98% of all known CVEs. Patch or mitigate before the next change window.
Description
On Zyxel NBG2105 V1.00(AAGU.2)C0 devices, setting the login cookie to 1 provides administrator access.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 20.51% probability · 98th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-287
- Affected
- zyxel/nbg2105 firmware
- Source
- cve@mitre.org
EPSS 20.5% since 3 November 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://codeberg.org/nieldk/vulnerabilities/src/branch/main/zyxel%20nbg2105/Admin%20bypass
- https://github.com/nieldk/vulnerabilities/blob/main/zyxel%20nbg2105/Admin%20bypassExploit, Third Party Advisory
- https://www.zyxel.com/support/SupportLandingSR.shtml?c=gb&l=en&kbid=M-01490&md=NBG2105Product, Vendor Advisory
- https://www.zyxel.com/us/en/support/security_advisories.shtmlVendor Advisory
- https://github.com/nieldk/vulnerabilities/blob/main/zyxel%20nbg2105/Admin%20bypassExploit, Third Party Advisory
- https://www.zyxel.com/support/SupportLandingSR.shtml?c=gb&l=en&kbid=M-01490&md=NBG2105Product, Vendor Advisory
- https://www.zyxel.com/us/en/support/security_advisories.shtmlVendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.