Vulnerability · Published Aug 25, 2026 · Assigned by VulnCheck
CVE-2026-56709Grav before 3.9.2 Host Header Injection via sendInvitationEmail
High 7.5
In plain English
A high-severity security flaw in grav from getgrav. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 38% of all known vulnerabilities).
Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.4%top 62.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
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 covers password reset flows.
Affected products (as reported)
Weakness: CWE-350 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
References
- GitHub Security Advisory (GHSA-69vf-mjxw-x79j) vendor-advisory
- VulnCheck Advisory: Grav before 3.9.2 Host Header Injection via sendInvitationEmail third-party-advisory