Summary
Formie: Unauthenticated users can overwrite incomplete submissions via submit action
Workarounds
No reliable workaround without upgrading. Disabling multi-page forms or save-for-later reduces exposure but does not remove the vulnerability.
- Reported by Jorge González ([email protected])
Impact
The anonymous front-end action formie/submissions/submit (SubmissionsController::actionSubmit) trusted a client-supplied submissionId when loading an incomplete submission, with no session binding, ownership check, or edit token validation.
An unauthenticated attacker could enumerate sequential submission IDs and overwrite or hijack another user's in-progress (multi-page / save-for-later) submission. Tampered data could be persisted and forwarded via notifications and integrations when the submission was completed.
Completed submissions were not affected (isIncomplete=true filter). This is an incomplete remediation of GHSA-pgxq-p76c-x9cg, which added edit-token validation to save-submission but not to submit.
The application does not perform an authorization check before performing a sensitive operation. Typical impact: unauthorized access to restricted functionality or data.
CVE-2026-76087 has a CVSS score of 8.2 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.1.31, 2.2.23); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Fixed in 3.1.31 (Craft 5) and 2.2.23 (Craft 4).
When resuming an existing submission on a site request, the submission ID must match the session-bound submission (Form::getCurrentSubmission()) or a valid submissionEditToken when editingSubmission is set. Cross-form submission ID reuse is also rejected.
Frequently Asked Questions
- What is CVE-2026-76087? CVE-2026-76087 is a high-severity missing authorization vulnerability in verbb/formie (composer), affecting versions >= 3.0.0, < 3.1.31. It is fixed in 3.1.31, 2.2.23. The application does not perform an authorization check before performing a sensitive operation.
- How severe is CVE-2026-76087? CVE-2026-76087 has a CVSS score of 8.2 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of verbb/formie are affected by CVE-2026-76087? verbb/formie (composer) versions >= 3.0.0, < 3.1.31 is affected.
- Is there a fix for CVE-2026-76087? Yes. CVE-2026-76087 is fixed in 3.1.31, 2.2.23. Upgrade to this version or later.
- Is CVE-2026-76087 exploitable, and should I be worried? Whether CVE-2026-76087 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-76087 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-76087?
- Upgrade
verbb/formieto 3.1.31 or later - Upgrade
verbb/formieto 2.2.23 or later
- Upgrade