CVE-2026-18330: Hardcoded Shared RSA-1024 Private Key in Web Login in TP-Link RE305 and Archer C7

Severity: medium (CVSS 6.1 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-03 · updated 2026-10-27
Weakness: CWE-321

Description

A hard-coded cryptographic key vulnerability exists in TP-Link RE305 V3 and Archer C7 V5. The same RSA-1024 private key is stored within firmware configuration files and reused across devices. An attacker who obtains the private key and captures an HTTP Web UI login session may use the key to decrypt the administrator password. Successful exploitation may disclose the administrator password captured from an HTTP login session and compromise session confidentiality.

Affected products

TP-Link Systems Inc. Archer C7 v5: before 1.3.1 Build 20260821 Rel. 41256 — fixed in 1.3.1 Build 20260821 Rel. 41256
TP-Link Systems Inc. RE305 v3: before 1.1.8 Build 20260921 Rel. 42853 — fixed in 1.1.8 Build 20260921 Rel. 42853

How to fix

Upgrade to a fixed version: TP-Link Systems Inc. Archer C7 v5 1.3.1 Build 20260821 Rel. 41256; TP-Link Systems Inc. RE305 v3 1.1.8 Build 20260921 Rel. 42853. Check the vendor advisory for mitigations.

References

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