CVE-2026-56709
Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/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:XCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-56709 is a high-severity Reliance on Reverse DNS Resolution for a Security-Critical Action (CWE-350) vulnerability. Its CVSS base score is 8.7 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 36th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to IA-3 (Device Identification and Authentication) and SC-20 (Secure Name/Address Resolution Service (Authoritative Source)) — see the control section below for these in your framework.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-65207
Vulnerability Data
Grav before 3.9.2 fails to validate untrusted Host headers in the sendInvitationEmail() function when constructing token-bearing invitation links. Attackers can manipulate the Host header to poison invitation links and redirect users to attacker-controlled domains, bypassing the require_trusted_host protection which only…
more
covers password reset flows.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Requiring unique device identification and authentication before any connection prevents security decisions based solely on unverified reverse DNS lookups.
Mandating data-origin authentication for name/address resolution stops reliance on unauthenticated reverse DNS responses.
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.
Monitoring DNS services can detect adverse events stemming from unverified reverse lookups.
Strong authentication of users/services/hardware directly prevents security decisions based on unauthenticated reverse DNS.
Network protections reduce the feasibility of attackers exploiting unauthenticated reverse-DNS decisions.
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.
Network security controls can enforce authenticated, non-DNS-based host identification.
Secure network services discourage use of unauthenticated reverse-DNS for access decisions.
Application security requirements can mandate authenticated host verification instead of reverse DNS.
Secure architecture principles discourage reliance on unauthenticated DNS for security decisions.
Secure coding practices can replace reverse-DNS checks with cryptographically verified identities.