← Vulnerability feed

Vulnerability record · CVE-2021-3297 · published 26 January 2021

CVE-2021-3297: Zyxel nbg2105 firmware improper authentication vulnerability

Zyxel · Nbg2105 Firmware

On Zyxel NBG2105 V1.00(AAGU.2)C0 devices, setting the login cookie to 1 provides administrator access.

7.8 CVSS 3.1 High EPSS 21% · top 2.6% CWE-287 · Improper authentication
7.8CVSS 3.1 base score, v2 7.2
21%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
7References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

On Zyxel NBG2105 V1.00(AAGU.2)C0 devices, setting the login cookie to 1 provides administrator access.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://codeberg.org/nieldk/vulnerabilities/src/branch/main/zyxel%20nbg2105/Admin%20bypass
https://github.com/nieldk/vulnerabilities/blob/main/zyxel%20nbg2105/Admin%20bypass ExploitThird Party Advisory
https://www.zyxel.com/support/SupportLandingSR.shtml?c=gb&l=en&kbid=M-01490&md=NBG2105 ProductVendor Advisory
https://www.zyxel.com/us/en/support/security_advisories.shtml Vendor Advisory
https://github.com/nieldk/vulnerabilities/blob/main/zyxel%20nbg2105/Admin%20bypass ExploitThird Party Advisory
https://www.zyxel.com/support/SupportLandingSR.shtml?c=gb&l=en&kbid=M-01490&md=NBG2105 ProductVendor Advisory
https://www.zyxel.com/us/en/support/security_advisories.shtml Vendor Advisory

Track CVE-2021-3297 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

7.5CVE-2026-42018JFrog Artifactory improper authentication leaks anonymous tokenJFrog Artifactory can return an internal anonymous-user token to an unauthenticated caller even when anonymous access is disabled. Because the token …KEVEPSS 9.8%analysed9.8CVE-2026-82329JFrog Artifactory improper authentication allows admin takeoverJFrog Artifactory contains an improper authentication weakness (CWE-287) that, under default configuration, may let an unauthenticated attacker with …KEVEPSS 14%analysed8.8CVE-2026-59822LiteLLM MCP endpoint auth bypass via OAuth2 passthrough fallbackLiteLLM's MCP Streamable HTTP endpoint, prior to 1.84.0, let an unauthenticated attacker send a fabricated Authorization header that triggered an OAu…KEVEPSS 0.84%analysed10.0CVE-2026-49869Kestra OSS auth bypass via path suffix match enables RCEKestra OSS AuthenticationFilter whitelists the public config endpoint using request.getPath().endsWith("/configs"), a suffix match instead of an exac…KEVEPSS 2.1%analysed9.8CVE-2023-49105ownCloud Server WebDAV authentication bypass via pre-signed URLsownCloud core before 10.13.1 accepts pre-signed URLs even when the file owner has no signing-key configured, so the signature check is effectively sk…KEVEPSS 43%analysed9.8CVE-2026-65400Apple macOS Screen Sharing authentication bypassAn improper authentication flaw in Apple macOS Screen Sharing allows a network attacker to authenticate without valid credentials. Apple fixed it via…KEVEPSS 1.2%analysed9.3CVE-2026-16232Check Point SmartConsole authentication bypass grants admin tokenCheck Point SmartConsole login contains an improper authentication flaw (CWE-287) that lets an unauthenticated remote attacker obtain an application …KEVEPSS 78%analysed9.8CVE-2026-46817Oracle E-Business Suite Payments missing authentication allows takeoverOracle Payments in Oracle E-Business Suite 12.2.3 through 12.2.15 contains an easily exploitable flaw in the File Transmission component. An unauthen…KEVEPSS 0.81%analysed

Source: NIST National Vulnerability Database (record CVE-2021-3297), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.