CVE-2026-56709

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 4.0

8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

CVSS 3.1

7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS

0.4% chance of exploitation in the next 30 days; higher than 37% of CVEs (scores of 2026-10-25)

CWE

CWE-350

Published

2026-08-25

Modified

2026-10-12

Record from

the NVD, synced 2026-10-19

References

• https://github.com/getgrav/grav/security/advisories/GHSA-69vf-mjxw-x79j
• https://www.vulncheck.com/advisories/grav-before-host-header-injection-via-sendinvitationemail

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