VulnerabilityPublished 4 Aug 2026

CVE-2026-8508: Zyxel WAX650S firmware · Improper Authentication

Affects Zyxel WAX650S firmwareSource CVE Database V5

Compare

Not known to be exploited · CVSS 6.5 Medium.

Data as of 2 Nov 2026, 22:58 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 24% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Adjacent
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Adjacent: The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 4 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: evidence found.
Public exploit code: GitHub proofs of concept
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), GitHub proofs of concept, the Metasploit, Exploit-DB and nuclei-templates index as of 2 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
ZyxelWAX650S firmware	Affected =<= 7.10(ABRM.4)C0	Fixed in–

AI-suggested

In the meantime, restricting WLAN access to trusted users and monitoring network activity may help reduce risk.

Description

CVE-2026-8508 is an improper authentication vulnerability in the Zyxel WAX650S firmware affecting versions up to 7.10(ABRM.4)C0. The flaw exists in the social_login.cgi CGI program and could allow an attacker connected to the WLAN to bypass captive portal authentication. The vulnerability has a CVSS 3.1 base score of 6.5, indicating a medium severity level. No official patch or remediation guidance has been provided by Zyxel as of the publication date. There are no known exploits in the wild. The vulnerability impacts confidentiality but does not affect integrity or availability.

Impact

An attacker on the WLAN can bypass captive portal authentication, potentially gaining unauthorized access to network resources or services that are normally restricted. The confidentiality of the network is impacted, but there is no indication of integrity or availability impact. This could lead to unauthorized network usage or data exposure within the WLAN environment.

Summary

This vulnerability (CVE-2026-8508) involves improper authentication (CWE-287) in the social_login.cgi CGI program of Zyxel WAX650S firmware versions through 7.10(ABRM.4)C0. It allows an attacker on the wireless LAN to bypass the captive portal authentication mechanism, potentially gaining unauthorized network access. The CVSS 3.1 vector indicates the attack requires adjacent network access (AV:A), has low attack complexity (AC:L), requires no privileges (PR:N), no user interaction (UI:N), and impacts confidentiality (C:H) without affecting integrity or availability.

CWE-287Improper Authentication (opens in a new tab)
Class weaknessLikelihood of exploit: HighOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Libraries or Frameworks
Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
OWASP Cheat Sheets
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V2.8.5 (opens in a new tab)
V2.8.4 (opens in a new tab)
V9.2.3 (opens in a new tab)
Attack patterns
Fake the Source of Data (opens in a new tab)
Utilizing REST's Trust in the System Resource to Obtain Sensitive Data (opens in a new tab)
Session Hijacking (opens in a new tab)
Token Impersonation (opens in a new tab)
Upload a Web Shell to a Web Server (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-command-injection-and-improper-authentication-vulnerabilities-in-certain-aps-fwa7-and-security-routers-08-04-2026 (opens in a new tab)

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 11 Aug 2026, 18:09 UTC

Public exploits and detectionGitHub proofs of concept

WeaknessesCWE-287

Technical details

References

Community reviews

Related threats