AC6 V5.0: Download of Code Without Integrity Check
CVE-2025-31355 is a critical-severity download of code without integrity check vulnerability in AC6 V5.0 from Tenda, 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 AC6 V5.0 versions: V02.03.01.110. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.32% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of AC6 V5.0 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 |
|---|---|---|---|
| Tenda | AC6 V5.0 | V02.03.01.110 | Not stated |
| Tenda | Ac6 Firmware | 02.03.01.110 | 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 NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.2 | High | CNA (cisco.com) |
| CVSS 3.1 | 9.8 | Critical | NVD |
Official description
A firmware update vulnerability exists in the Firmware Signature Validation functionality of Tenda AC6 V5.0 V02.03.01.110. A specially crafted malicious file can lead to arbitrary code execution. An attacker can provide a malicious file to trigger this vulnerability.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Download of Code Without Integrity Check
The product downloads source code or an executable from a remote location and executes the code without sufficiently verifying the origin and integrity of the code.
How developers prevent this class of flaw
- Perform proper forward and reverse DNS lookups to detect DNS spoofing.
- Encrypt the code with a reliable encryption scheme before transmitting.
- Run your code using the lowest privileges that are required to accomplish the necessary tasks. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.
More Download of Code Without Integrity Check vulnerabilities (CWE-494)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- talosintelligence.com/vulnerability_reports/TALOS-2025-2161Third Party Advisory
Other references
Other vulnerabilities in AC6 V5.0
- 9.8 Critical severity
- 7.5 High severity
- 9.8 Critical severity
- 7.5 High severity
- 9.8 Critical severity
Recent Download of Code Without Integrity Check vulnerabilities
- 8.8 High severity
- 9.3 Critical severity
- 8.8 High severity
- 9.3 Critical severity
- 7.5 High severity
- 8.2 High severity
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