Improper access control in erb - CVE-2026-41316
Published: April 21, 2026 / Updated: April 21, 2026
Vulnerability identifier: #VU126644
CSH Severity: High
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
CVE-ID: CVE-2026-41316
CWE-ID: CWE-284
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Ruby
Affected software:
erb
erb
Detailed vulnerability description
The vulnerability allows a remote attacker to execute arbitrary code.
The vulnerability exists due to improper access control in ERB#def_module, ERB#def_method, and ERB#def_class when deserializing untrusted data with Marshal.load. A remote attacker can supply crafted serialized data to bypass the @_init guard and execute arbitrary code.
Exploitation requires both erb and activesupport to be loaded.
How to mitigate CVE-2026-41316
Install security update from vendor's website.