CVE-2026-56709
Host header injection in Grav <3.9.2 allows poisoned invitation links to attacker domains
Is CVE-2026-56709 being exploited?
Not confirmed. CVE-2026-56709 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.26% probability of exploitation in the next 30 days.
How severe is CVE-2026-56709?
CVE-2026-56709 is rated High with a CVSS score of 8.7. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-56709?
Yes. A fix has been recorded for CVE-2026-56709. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-56709 affect?
CVE-2026-56709 affects Grav CMS < 3.9.2, Self-hosted Grav sites using sendInvitationEmail(). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-56709?
Upgrade to Grav 3.9.2+, validate Host header handling, rotate affected tokens
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Host header manipulation crafts token-bearing invitation links that redirect to attacker domains, enabling phishing, token theft and account compromise.
Immediate action required
- affected< 3.9.2
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.