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HIGH · 8.1

CVE-2026-41316

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 ...

Vulnerability 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.

CVSS Score

8.1

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH

Related Weaknesses (CWE)

CWE-693

References

FAQ

What is CVE-2026-41316?

CVE-2026-41316 is a vulnerability with a CVSS score of 8.1 (HIGH). 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 ...

How severe is CVE-2026-41316?

CVE-2026-41316 has been rated HIGH with a CVSS base score of 8.1/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-41316?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.