CVE-2026-12490
Published: 25 June 2026
Summary
CVE-2026-12490 is a high-severity Improper Access Control (CWE-284) vulnerability in Nlnetlabs Nsd. Its CVSS base score is 8.2 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 3.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-39185
Vulnerability details
When a provide-xfr is given with a tls-auth-name, a secondary requesting a transfer should provide a client certificate with that name. However, no client certificate is needed when the request comes in over TLS over the regular tls-port (and not…
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the tls-auth-port) or over over TCP over the regular port, when the other conditions of the provide-xfr rule match.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Auth bypass in public-facing DNS service directly enables exploitation of the application for unauthorized zone transfers.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Device lock enforces restricted access until re-authentication, directly reducing unauthorized use of active sessions.
Explicitly identifying and documenting actions permitted without identification or authentication enforces proper access control boundaries by defining justified exceptions.
Requiring authorization and configuration controls for mobile device connections directly enforces access control and prevents unauthorized devices from reaching organizational systems.
Provides a tamperproof, always-invoked, and verifiable mechanism to enforce access control policies.
Provides capability to review session content, directly detecting violations of access control.
Control assessments verify that access controls are implemented correctly and operating as intended, detecting improper access control before exploitation.
Certification requires independent assessment confirming access controls are implemented correctly and effective.
Restricting available functions and services reduces the attack surface and enforces proper access control boundaries.