High severity · published Aug 25, 2026
CVE-2026-56709
Grav before 3.9.2 Host Header Injection via sendInvitationEmail
7.5
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 38% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
GR
grav · getgrav
before 3.9.2 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-56709
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-56709
github.com
https://github.com/getgrav/grav/security/advisories/GHSA-69vf-mjxw-x79j
www.vulncheck.com
https://www.vulncheck.com/advisories/grav-before-host-header-injection-via-sendinvitationemail
More from grav
9.9
CVE-2024-34082
Grav is a file-based Web platform
9.8
CVE-2026-80203
Grav before 1.0.18 Authentication Bypass via Scoped API Key
9.8
CVE-2026-56710
Grav Login Plugin before 1.0.16 Privilege Escalation via Unlock
9.8
CVE-2026-65008
Grav before 2.0.7 Remote Code Execution via Blueprint dynamicData
9.8
CVE-2021-47812
GravCMS 1.10.7 - Arbitrary YAML Write/Update (Unauthenticated) (2)