# CVE-2026-38142: Tenda AC18 command injection in fast_setting_internet_set

Source: https://junglewise.ai/threats/cve-2026-38142-tenda-ac18-command-injection-in-fast-setting-internet-set  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-01. Updated: 2026-07-01  
License: CC BY 4.0 with a link back

CVE-2026-38142 · Severity: medium · CVSS 6.5 · Published 2026-07-01

A security vulnerability has been identified in the Tenda AC18 router, a device used to provide wireless internet access. An unauthorized person could remotely send a specially crafted request to the router to take control of the device. This could allow an attacker to disrupt internet service or potentially monitor network traffic.

Technologies: [Tenda AC18](https://junglewise.ai/threats/technologies/ac18). Vendors: [Tenda](https://junglewise.ai/threats/vendors/tenda).

## Quick answers

**Is CVE-2026-38142 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-38142 being exploited in the wild.

**How severe is CVE-2026-38142?** Medium severity, with a CVSS score of 6.5, published 1 July 2026.

**Which products and versions are affected?** Tenda AC18 v15.03.05.05.

**Is there a fix for CVE-2026-38142?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-38142 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-38142?** Check whether you run Tenda AC18 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A command injection vulnerability (CWE-77) exists in the Tenda AC18 router running firmware version v15.03.05.05. The flaw is located within the '/goform/fast_setting_internet_set' endpoint, which fails to properly sanitize the 'mac' input parameter. An unauthenticated remote attacker can exploit this by sending a malicious HTTP request containing shell metacharacters in the MAC address field. Successful exploitation allows for arbitrary OS command execution on the underlying system. The vulnerability is described as second-order in some documentation, suggesting the injected payload may be stored and executed during a subsequent process.

## Affected products

- Tenda AC18 v15.03.05.05

## Timeline

- 2026-07-01: advisory: CVE-2026-38142 published by NVD

## References

- [https://github.com/longqx223/Tenda-ac-18-V15.03.05.05-/blob/main/Tenda%20AC18%20Unauthenticated%20Second-Order%20OS%20Command%20Injection%20in%20goformfast_setting_internet_set.pdf](https://github.com/longqx223/Tenda-ac-18-V15.03.05.05-/blob/main/Tenda%20AC18%20Unauthenticated%20Second-Order%20OS%20Command%20Injection%20in%20goformfast_setting_internet_set.pdf)

## Related threats

- [Tenda AC18 authentication bypass in telnet handler](https://junglewise.ai/threats/cve-2026-82695-tenda-ac18-authentication-bypass-in-telnet-handler)
- [A command injection vulnerability exists in Tenda AC18 V15.03.05.05_multi. The vulnerability is located in the…](https://junglewise.ai/threats/cve-2026-31255-a-command-injection-vulnerability-exists-in-tenda-ac18-v15-03-05)
- [A vulnerability was detected in Tenda AC18 15.03.05.05. This affects the function sprintf of the file…](https://junglewise.ai/threats/cve-2025-14993-a-vulnerability-was-detected-in-tenda-ac18-15-03-05-05-this)
- [A security vulnerability has been detected in Tenda AC18 15.03.05.05. The impacted element is the function strcpy of…](https://junglewise.ai/threats/cve-2025-14992-a-security-vulnerability-has-been-detected-in-tenda-ac18-15-03-05)