CVE-2026-56709
Grav before 3.9.2 Host Header Injection via sendInvitationEmail
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.
INFO
Published Date :
Aug. 25, 2026, 2:16 a.m.
Last Modified :
Oct. 12, 2026, 3:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | MITRE-CVE | ||||
| CVSS 4.0 | HIGH | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update Grav to version 3.9.2 or later.
- Ensure Host header validation is properly configured.
- Monitor invitation link generation for suspicious activity.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-56709.
| URL | Resource |
|---|---|
| https://github.com/getgrav/grav/security/advisories/GHSA-69vf-mjxw-x79j | |
| https://www.vulncheck.com/advisories/grav-before-host-header-injection-via-sendinvitationemail |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-56709 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-56709
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-56709 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-56709 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 12, 2026
Action Type Old Value New Value Added Translation Title: Grav de getgrav, Description: Grav anterior a la versión 3.9.2 no valida los encabezados Host no confiables en la función sendInvitationEmail() al construir enlaces de invitación con token. Los atacantes pueden manipular el encabezado Host para envenenar enlaces de invitación y redirigir a los usuarios a dominios controlados por el atacante, eludiendo la protección require_trusted_host que solo cubre los flujos de restablecimiento de contraseña. -
CVE Modified by [email protected]
Aug. 26, 2026
Action Type Old Value New Value Added Reference https://github.com/getgrav/grav/security/advisories/GHSA-69vf-mjxw-x79j Added Reference https://www.vulncheck.com/advisories/grav-before-host-header-injection-via-sendinvitationemail Removed Reference https://github.com/getgrav/grav/security/advisories/GHSA-69vf-mjxw-x79j Removed Reference https://www.vulncheck.com/advisories/grav-before-host-header-injection-via-sendinvitationemail -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Aug. 26, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-56709', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-08-26T15:58:34.294788Z'} -
New CVE Received by [email protected]
Aug. 25, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'getgrav', 'product': 'grav', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '3.9.2', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '3.9.2', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}] Added 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. Added CVSS V4.0 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:X Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Added CWE CWE-350 Added Reference https://github.com/getgrav/grav/security/advisories/GHSA-69vf-mjxw-x79j Added Reference https://www.vulncheck.com/advisories/grav-before-host-header-injection-via-sendinvitationemail