CVSS Vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Lifecycle Timeline
4Description
Incorrect Authorization vulnerability in Erlang OTP (inets modules) allows unauthenticated access to CGI scripts protected by directory rules when served via script_alias. When script_alias maps a URL prefix to a directory outside DocumentRoot, mod_auth evaluates directory-based access controls against the DocumentRoot-relative path while mod_cgi executes the script at the ScriptAlias-resolved path. This path mismatch allows unauthenticated access to CGI scripts that directory rules were meant to protect. This vulnerability is associated with program files lib/inets/src/http_server/mod_alias.erl, lib/inets/src/http_server/mod_auth.erl, and lib/inets/src/http_server/mod_cgi.erl. This issue affects OTP from OTP 17.0 until OTP 28.4.2, 27.3.4.10 and 26.2.5.19 corresponding to inets from 5.10 until 9.6.2, 9.3.2.4 and 9.1.0.6.
Analysis
Authorization bypass in Erlang OTP's inets HTTP server allows unanauthenticated remote attackers to execute CGI scripts protected by directory-level access controls. The vulnerability stems from a path mismatch where mod_auth validates access against DocumentRoot-relative paths while mod_cgi executes scripts at ScriptAlias-resolved paths outside DocumentRoot. …
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Remediation
Within 24 hours: Audit all Erlang OTP deployments to identify versions 17.0-28.4.1 and confirm presence of both mod_auth and mod_cgi with ScriptAlias directives. Within 7 days: Apply vendor-released patches to upgrade affected OTP versions to 28.4.2 or later (or equivalent security releases for earlier branches). …
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EUVD-2026-19602