# CVE-2026-76087: Formie: Unauthenticated users can overwrite incomplete submissions via submit action

> Unauthenticated attackers can overwrite other users' incomplete form submissions by manipulating submission IDs, leading to data modification and potential exposure.

- **Severity:** High 8.2 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 23 Sep 2026
- **Updated:** 24 Sep 2026
- **Also known as:** GHSA-584p-f93j-wpgc

## What is CVE-2026-76087?

CVE-2026-76087 is a high-severity missing authorization vulnerability in verbb formie, published on 23 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Formie is a Craft CMS plugin for creating forms. Prior to 2.2.23 and 3.1.31, Formie's anonymous formie/submissions/submit action in SubmissionsController::actionSubmit trusts a client-supplied submissionId when loading an incomplete submission without session binding, ownership validation, or a valid submissionEditToken. An unauthenticated attacker can enumerate sequential IDs and overwrite or hijack another user's in-progress multi-page or save-for-later submission, and the modified data can be persisted and forwarded through notifications or integrations when the submission is completed. This is an incomplete remediation of CVE-2026-47266 because that earlier change validated edit tokens for save-submission but did not protect submit. Completed submissions are excluded by the isIncomplete filter. This issue is fixed in versions 2.2.23 and 3.1.31.

Weakness: CWE-862 (Missing Authorization), CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-76087?

4 open source packages ship an affected version, including verbb/formie.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `verbb/formie` | Packagist | All versions | 2.2.23 |
| `verbb/formie` | Packagist | All versions | 2.2.23 |
| `verbb/formie` | Packagist | From 3.0.0 | 3.1.31 |
| `verbb/formie` | Packagist | From 3.0.0 | 3.1.31 |

## How do I fix CVE-2026-76087?

Upgrade verbb/formie to a fixed version for your release line: 2.2.23 or 3.1.31.

## Is CVE-2026-76087 being exploited?

There is no known exploitation of CVE-2026-76087 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-76087 and fix it if it is affected.

What it is: CVE-2026-76087 is a high-severity missing authorization vulnerability in verbb formie, published on 23 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-76087 in the wild and no public exploit code.

Affected packages and fixed versions:
- verbb/formie (Packagist): affected all versions; fixed in 2.2.23
- verbb/formie (Packagist): affected all versions; fixed in 2.2.23
- verbb/formie (Packagist): affected from 3.0.0; fixed in 3.1.31
- verbb/formie (Packagist): affected from 3.0.0; fixed in 3.1.31

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-76087/ (Markdown: https://insights.sbomify.com/CVE-2026-76087/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-76087
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-76087
- OSV: https://osv.dev/vulnerability/CVE-2026-76087

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-76087/
Summaries are generated and may contain mistakes; the official description above is the record.