L3_V2_8: Channel Accessible by Non-Endpoint
CVE-2026-74232 is a critical-severity channel accessible by non-endpoint vulnerability in L3_V2_8 from Zbtlink, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected L3_V2_8 versions: 3.0.0.4.528. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.81% chance of exploitation within 30 days, higher than 58% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of L3_V2_8 you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Zbtlink | L3_V2_8 | 3.0.0.4.528 | Not stated |
| Zbtlink | WE826-T2 | 19.1101 | Not stated |
| Zbtlink | ZBT-7628 | 1.0.0.2.007 | Not stated |
| Zbtlink | ZBT-ZBT7621 | 1.0.0.3.001 | Not stated |
| MoreQuick | MQAC-7620 | 1.0.0.2.000 | Not stated |
| MoreQuick | MQAC-7620A | 1.0.0.2.000 | Not stated |
| MoreQuick | MQAP-7620 | 1.0.0.2.000 | Not stated |
| MoreQuick | MQAP-7620A | 1.0.0.2.000 | Not stated |
| MoreQuick | MQAP-7628 | 1.0.0.2.000 | Not stated |
| AP522 | AP522 | 1.0.0.2.014 | Not stated |
| AP7628 | AP7628 | 3.0.0.4.380 | Not stated |
| APG721B | APG721B | 19.0809 | Not stated |
| HC5661A | HC5661A | 3.0.0.4.380 | Not stated |
| HK300 | HK300 | 1.0.0.2.032 | Not stated |
| MAP-N10 | MAP-N10 | 1.0.0.2.044 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (vulncheck.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 9.3 | Critical | CNA (vulncheck.com) |
| CVSS 3.1 | 9.8 | Critical | CNA (vulncheck.com) |
Official description
Zbtlink L3_V2_8 firmware 3.0.0.4.528, Zbtlink WE826-T2 firmware 19.1101, Zbtlink ZBT-7628 firmware 1.0.0.2.007, Zbtlink ZBT-ZBT7621 firmware 1.0.0.3.001, MoreQuick MQAC-7620, MQAC-7620A, MQAP-7620, MQAP-7620A, and MQAP-7628 firmware 1.0.0.2.000, AP522 firmware 1.0.0.2.014, AP7628 and HC5661A firmware 3.0.0.4.380, APG721B firmware 19.0809, HK300 firmware 1.0.0.2.032, and MAP-N10 firmware 1.0.0.2.044 ship a backdoor command-and-control implant (yunmgrd) reachable over an unauthenticated cleartext UDP channel to a hardcoded C2 server. A remote unauthenticated attacker on the network path can hijack the channel and execute arbitrary commands as root. The attacker can also modify DNS entries, exfiltrate PPPoE credentials, and open reverse SSH tunnels.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Channel Accessible by Non-Endpoint
The product does not adequately verify the identity of actors at both ends of a communication channel, or does not adequately ensure the integrity of the channel, in a way that allows the channel to be accessed or influenced by an actor that is not an endpoint.
How developers prevent this class of flaw
- In order to establish secure communication between two parties, it is often important to adequately verify the identity of entities at each end of the communication channel. Always fully authenticate both ends of any communications channel.
- Adhere to the principle of complete mediation.
- A certificate binds an identity to a cryptographic key to authenticate a communicating party. Often, the certificate takes the encrypted form of the hash of the identity of the subject, the public key, and information such as time of issue or expiration using the issuer's private key. The certificate can be validated by deciphering the certificate with the issuer's public key. See also X.509 certificate signature chains and the PGP certification structure.
More Channel Accessible by Non-Endpoint vulnerabilities (CWE-300)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Recent Channel Accessible by Non-Endpoint vulnerabilities
- 8.7 High severity
- 7.0 High severity
- 8.1 High severity
- 7.8 High severity
- 7.5 High severity
- 7.5 High severity
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