AC9: Improper Authentication
CVE-2026-86300 is a high-severity improper authentication vulnerability in AC9 from Tenda, with a CVSS 3.1 base score of 7.3 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected AC9 versions: 15.03.05.14. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.84% chance of exploitation within 30 days, higher than 59% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of AC9 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
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
- LowSome restricted data can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- LowPerformance or availability is reduced.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L. Scored by CNA (vuldb.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 5.5 | Medium | CNA (vuldb.com) |
| CVSS 3.1 | 7.3 | High | CNA (vuldb.com) |
| CVSS 2.0 | 7.5 | High | CNA (vuldb.com) |
Official description
A flaw has been found in Tenda AC9 15.03.05.14. This impacts the function R7WebsSecurityHandler of the component Web Management. This manipulation causes improper authentication. The attack may be initiated remotely. The exploit has been published and may be used.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Authentication
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
How developers prevent this class of flaw
- Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other references
- github.com/limou89/somevul/blob/main/Tenda_AC9_fast_setting_wifi_set_Unauth_Password.md
- github.com/limou89/somevul/blob/main/Tenda_AC9_getProduct_Info_Disclosure.md
- vuldb.com/cve/CVE-2026-86300
- vuldb.com/submit/906606
- vuldb.com/submit/906607
- vuldb.com/submit/906608
- vuldb.com/vuln/399464
- vuldb.com/vuln/399464/cti
- tenda.com.cn/
Other vulnerabilities in AC9
- 9.1 Critical severity
- 8.8 High severity
- 8.8 High severity
- 7.2 High severity
- 7.2 High severity
- 7.5 High severity
Recent Improper Authentication vulnerabilities
- 9.8 Critical severity
- 9.8 Critical severity
- 7.3 High severity
- 7.3 High severity
- 7.3 High severity
- 9.8 Critical severity
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