CVE-2026-41316
CVE-2026-41316 · ERB has an @_init deserialization guard bypass via def_module / def_method / def_class
This page contains facts from public vulnerability sources. Check the original advisory before updating.
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.
CVSS 8.1 · High · EPSS 1.1%
- Published
- Updated
Stack: system
Affected products and versions
erb
- Versions
- < 4.0.3.1: Affected
- = 4.0.4: Affected
- >= 5.0.0, < 6.0.1.1: Affected
- >= 6.0.2, < 6.0.4: Affected
No fix published
ruby3.1 Debian:12
- Versions
- 3.1.2-7
- 3.1.2-7+deb12u1
- 3.1.2-7+hurd.1
- 3.1.2-8
- 3.1.2-8.1~exp1
- 3.1.2-8.3
- 3.1.2-8.4
- 3.1.2-8.5
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
ruby3.3 Debian:13
- Versions
- 3.3.8-2
- 3.3.8-2.1
- 3.3.8-2.2
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
ruby3.3 Debian:14
- Versions
- 3.3.8-2
- 3.3.8-2.1
- 3.3.8-2.2
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
jruby Ubuntu:Pro:14.04:LTS
- Versions
- 1.5.6-5ubuntu1
- 1.5.6-6
- 1.5.6-7
- 1.5.6-9+deb8u2build0.14.04.1~esm2
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
ruby2.3 Ubuntu:Pro:16.04:LTS
- Versions
- 2.3.0-1
- 2.3.0-2
- 2.3.0-4ubuntu2
- 2.3.0-4ubuntu3
- 2.3.0-5ubuntu1
- 2.3.1-2~16.04
- 2.3.1-2~16.04.2
- 2.3.1-2~16.04.4
- 2.3.1-2~16.04.5
- 2.3.1-2~16.04.6
- 2.3.1-2~16.04.7
- 2.3.1-2~16.04.9
- 2.3.1-2~16.04.10
- 2.3.1-2~16.04.11
- 2.3.1-2~16.04.12
- 2.3.1-2~ubuntu16.04.13
- 2.3.1-2~ubuntu16.04.14
- 2.3.1-2~ubuntu16.04.15
- 2.3.1-2~ubuntu16.04.16
- 2.3.1-2~ubuntu16.04.16+esm1
- 2.3.1-2~ubuntu16.04.16+esm2
- 2.3.1-2~ubuntu16.04.16+esm3
- 2.3.1-2~ubuntu16.04.16+esm4
- 2.3.1-2~ubuntu16.04.16+esm5
- 2.3.1-2~ubuntu16.04.16+esm6
- 2.3.1-2~ubuntu16.04.16+esm7
- 2.3.1-2~ubuntu16.04.16+esm8
- 2.3.1-2~ubuntu16.04.16+esm9
- 2.3.1-2~ubuntu16.04.16+esm10
- 2.3.1-2~ubuntu16.04.16+esm11
- 2.3.1-2~ubuntu16.04.16+esm12
- 2.3.1-2~ubuntu16.04.16+esm14
- 2.3.1-2~ubuntu16.04.16+esm15
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
jruby Ubuntu:16.04:LTS
- Versions
- 1.7.21-2ubuntu4
- 1.7.22-1ubuntu1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
ruby2.5 Ubuntu:Pro:18.04:LTS
- Versions
- 2.5.0~preview1-1ubuntu2
- 2.5.0-4ubuntu1
- 2.5.0-4ubuntu4
- 2.5.0-5ubuntu1
- 2.5.0-6ubuntu1
- 2.5.1-1ubuntu1
- 2.5.1-1ubuntu1.1
- 2.5.1-1ubuntu1.2
- 2.5.1-1ubuntu1.4
- 2.5.1-1ubuntu1.5
- 2.5.1-1ubuntu1.6
- 2.5.1-1ubuntu1.7
- 2.5.1-1ubuntu1.8
- 2.5.1-1ubuntu1.9
- 2.5.1-1ubuntu1.10
- 2.5.1-1ubuntu1.11
- 2.5.1-1ubuntu1.12
- 2.5.1-1ubuntu1.13
- 2.5.1-1ubuntu1.14
- 2.5.1-1ubuntu1.15
- 2.5.1-1ubuntu1.16
- 2.5.1-1ubuntu1.16+esm1
- 2.5.1-1ubuntu1.16+esm3
- 2.5.1-1ubuntu1.16+esm4
- 2.5.1-1ubuntu1.16+esm5
- 2.5.1-1ubuntu1.16+esm6
- 2.5.1-1ubuntu1.16+esm7
- 2.5.1-1ubuntu1.16+esm8
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
jruby Ubuntu:18.04:LTS
- Versions
- 9.1.13.0-1
- 9.1.17.0-1~18.04
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
ruby2.7 Ubuntu:Pro:20.04:LTS
- Versions
- 2.7.0-1
- 2.7.0-2
- 2.7.0-3
- 2.7.0-4
- 2.7.0-4ubuntu1
- 2.7.0-5ubuntu1
- 2.7.0-5ubuntu1.1
- 2.7.0-5ubuntu1.2
- 2.7.0-5ubuntu1.3
- 2.7.0-5ubuntu1.4
- 2.7.0-5ubuntu1.5
- 2.7.0-5ubuntu1.6
- 2.7.0-5ubuntu1.7
- 2.7.0-5ubuntu1.8
- 2.7.0-5ubuntu1.9
- 2.7.0-5ubuntu1.10
- 2.7.0-5ubuntu1.11
- 2.7.0-5ubuntu1.12
- 2.7.0-5ubuntu1.13
- 2.7.0-5ubuntu1.14
- 2.7.0-5ubuntu1.15
- 2.7.0-5ubuntu1.16
- 2.7.0-5ubuntu1.17
- 2.7.0-5ubuntu1.18
- 2.7.0-5ubuntu1.18+esm1
- 2.7.0-5ubuntu1.18+esm3
- 2.7.0-5ubuntu1.18+esm4
- 2.7.0-5ubuntu1.18+esm5
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
jruby Ubuntu:20.04:LTS
- Versions
- 9.1.17.0-3
- 9.1.17.0-3build5
- 9.1.17.0-3build6
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
ruby3.0 Ubuntu:22.04:LTS
- Versions
- 3.0.2-5ubuntu1
- 3.0.2-7
- 3.0.2-7ubuntu2
- 3.0.2-7ubuntu2.1
- 3.0.2-7ubuntu2.2
- 3.0.2-7ubuntu2.3
- 3.0.2-7ubuntu2.4
- 3.0.2-7ubuntu2.5
- 3.0.2-7ubuntu2.6
- 3.0.2-7ubuntu2.7
- 3.0.2-7ubuntu2.8
- 3.0.2-7ubuntu2.10
- 3.0.2-7ubuntu2.11
- 3.0.2-7ubuntu2.12
- 3.0.2-7ubuntu2.13
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
jruby Ubuntu:24.04:LTS
- Versions
- 9.3.9.0+ds-1
- 9.4.5.0+ds-1
- 9.4.5.0+ds-1ubuntu1
- 9.4.6.0+ds-1ubuntu3
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
ruby3.2 Ubuntu:24.04:LTS
- Versions
- 3.2.3-1
- 3.2.3-1build2
- 3.2.3-1build3
- 3.2.3-1ubuntu0.24.04.1
- 3.2.3-1ubuntu0.24.04.3
- 3.2.3-1ubuntu0.24.04.5
- 3.2.3-1ubuntu0.24.04.6
- 3.2.3-1ubuntu0.24.04.7
- 3.2.3-1ubuntu0.24.04.8
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
jruby Ubuntu:25.10
- Versions
- 9.4.8.0+ds-2ubuntu1
- 9.4.8.0+ds-3ubuntu1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
ruby3.3 Ubuntu:25.10
- Versions
- 3.3.7-1ubuntu2
- 3.3.8-2ubuntu1
- 3.3.8-2ubuntu2
- 3.3.8-2ubuntu2.1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
jruby Ubuntu:26.10
- Versions
- 9.4.8.0+ds-3ubuntu1
- 9.4.14.0+ds-1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
ruby3.3 Ubuntu:26.10
- Versions
- 3.3.8-2ubuntu3
- 3.3.8-2.2ubuntu4
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
jruby Ubuntu:26.04:LTS
- Versions
- 9.4.8.0+ds-3ubuntu1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
ruby3.3 Ubuntu:26.04:LTS
- Versions
- 3.3.8-2ubuntu2
- 3.3.8-2ubuntu3
- 3.3.8-2ubuntu3.1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
Original sources
- https://github.com/ruby/erb/security/advisories/GHSA-q339-8rmv-2mhv
- https://access.redhat.com/security/cve/CVE-2026-41316
- https://bugzilla.redhat.com/show_bug.cgi?id=2461369
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-41316.json
- https://access.redhat.com/errata/RHSA-2026:33478
- https://access.redhat.com/errata/RHSA-2026:18065
- https://access.redhat.com/errata/RHSA-2026:20606
- https://access.redhat.com/errata/RHSA-2026:20614
- https://access.redhat.com/errata/RHSA-2026:20670
- https://access.redhat.com/errata/RHSA-2026:35834
- https://access.redhat.com/errata/RHSA-2026:26312
- https://access.redhat.com/errata/RHSA-2026:26655
- https://access.redhat.com/errata/RHSA-2026:33462
- https://access.redhat.com/errata/RHSA-2026:37238
- https://access.redhat.com/errata/RHSA-2026:18039
- https://access.redhat.com/errata/RHSA-2026:18030
- https://access.redhat.com/errata/RHSA-2026:20596
- https://nvd.nist.gov/vuln/detail/CVE-2026-41316