Detections
Analytics
CVE-2026-41316
high
Description
ERB is a templating system for Ruby. Ruby 2.7.0 (before ERB 2.2.0 was published on rubygems.org) introduced an `@_init` instance variable guard in `ERB#result` and `ERB#run` to prevent code execution when an ERB object is reconstructed via `Marshal.load` (deserialization). However, three other public methods that also evaluate `@src` via `eval()` were not given the same guard: `ERB#def_method`, `ERB#def_module`, and `ERB#def_class`. An attacker who can trigger `Marshal.load` on untrusted data in a Ruby application that has `erb` loaded can use `ERB#def_module` (zero-arg, default parameters) as a code execution sink, bypassing the `@_init` protection entirely. ERB 4.0.3.1, 4.0.4.1, 6.0.1.1, and 6.0.4 patch the issue.
References
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-41316.json
https://github.com/ruby/erb/security/advisories/GHSA-q339-8rmv-2mhv
https://bugzilla.redhat.com/show_bug.cgi?id=2461369
https://access.redhat.com/security/cve/CVE-2026-41316
https://access.redhat.com/errata/RHSA-2026:33478
https://access.redhat.com/errata/RHSA-2026:33462
https://access.redhat.com/errata/RHSA-2026:26655
https://access.redhat.com/errata/RHSA-2026:26312
https://access.redhat.com/errata/RHSA-2026:20670
https://access.redhat.com/errata/RHSA-2026:20614
https://access.redhat.com/errata/RHSA-2026:20606
https://access.redhat.com/errata/RHSA-2026:20596
https://access.redhat.com/errata/RHSA-2026:18065