Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
The simple_form RubyGems package is affected in versions below 5.0.0, and the fix is in 5.0.0. An attacker can exploit this when a page builds a form from user-supplied input, by supplying a string that is invoked as a method call on the form's object, which can enable code execution, denial of service, or information disclosure. Upgrade to simple_form 5.0.0 or later; if upgrading is not possible, explicitly set the input type with the `as` option so Simple Form does not infer it from user input.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 9.8 | Critical | 3.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H | GitHub Advisory Database |
- CISA KEV Not listed.
- EPSS 0.034, the 88th percentile, on 10 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 15:16 UTC First seen by agentprime
- 31 Oct 2026, 15:16 UTC Confirmed by OSV
Sources
- GitHub Advisory Database: GHSA-r74q-gxcg-73hx
- OSV: GHSA-r74q-gxcg-73hx
- github.com/plataformatec/simple_form/security/advisories/GHSA-r74q-gxcg-73hx
- nvd.nist.gov/vuln/detail/CVE-2019-16676
- github.com/heartcombo/simple_form/commit/8c91bd76a5052ddf3e3ab9fd8333f9aa7b2e2dd6
- github.com/advisories/GHSA-r74q-gxcg-73hx
- github.com/heartcombo/simple_form
- github.com/plataformatec/simple_form/commits/master
- github.com/rubysec/ruby-advisory-db/blob/master/gems/simple_form/CVE-2019-16676.yml
- blog.plataformatec.com.br/2019/09/incorrect-access-control-in-simple-form-cve-2019-16676