CVE-2026-5039
Tp-Link Tl-Wr841N Firmware ≤ 231120
Raw vector
CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XSummary
CVE-2026-5039 is a medium-severity Use of Default Cryptographic Key (CWE-1394) vulnerability in Tp-Link Tl-Wr841N Firmware. Its CVSS base score is 6.1 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Private Keys (T1552.004); ranked at the 3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to CM-6 (Configuration Settings) and SC-12 (Cryptographic Key Establishment and Management) — see the control section below for these in your framework.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-25250
Vulnerability Data
TP-Link TL-WR841N v13 uses DES-CBC encryption in the TDDPv2 debug protocol with a cryptographic key derived from default web management credentials, making the key predictable if device is left in default configuration. A network-adjacent attacker can exploit this weakness to…
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gain unauthorized access to the protocol, read debug data, modify certain device configuration values, and trigger device reboot, resulting in loss of integrity and a denial-of-service condition.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Cryptographic key establishment and management requires generating and provisioning unique keys rather than relying on manufacturer defaults.
Requiring the most restrictive configuration settings prohibits the use of known default cryptographic keys.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Configuration management directly prohibits default keys via hardened baselines and change control.
Credential/key management practices eliminate default cryptographic keys for identities and services.
Strong authentication requirements implicitly disallow default keys but do not address key management itself.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Mandates proper key management, directly preventing use of default cryptographic keys.
Enforces secure configuration baselines that should replace default keys.
Controls software installation and configuration, reducing risk of default keys being left in place.
Change-management processes should detect and remediate default cryptographic keys.
Requires secure authentication mechanisms that would be undermined by default keys.