AIKIDO-2026-527558
plug is vulnerable to Cookie Attribute Injection
21
Low Risk
This Affects:
plugTL;DR
Plug.Conn.Cookies.encode/2 in the Elixir plug library builds the Set-Cookie response header by interpolating the cookie path, domain and same_site attributes directly into the header string without validating the ; character. Any Plug application that reflects attacker-controlled data into a cookie attribute lets an unauthenticated attacker inject additional cookie attributes through ;. Plug already handles and null bytes accordingly, so header injection is not possible.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range.
Background info
plug is vulnerable to Cookie Attribute Injection in versions 0.1.0 - 1.16.5, 1.17.0 - 1.17.3, 1.18.0 - 1.18.4, 1.19.0 - 1.19.4 and 1.20.0 - 1.20.2.
How to fix this
Upgrade the plug library to the patch version.
Links
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SOC 2Compliant
ISO 27001Compliant