CVE-2026-28808

Critical · CVSS 9.8

Erlang OTP inets — Incorrect Authorization / Authentication Bypass via path mismatch in CGI script_alias

CVSS: 9.8; nvd
EPSS: 0.54%; 44th pct
KEV: No
Class: oss containerizable; CWE-863, CWE-551

Description

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 before OTP 26.2.5.19, OTP 27.3.4.10, and OTP 28.4.2, corresponding to inets from 5.10 before 9.1.0.6, 9.3.2.4, and 9.6.2. Whether OTP before OTP 17.0, corresponding to inets before 5.10, is affected is unknown.

Search profile — drives PoC discovery

Symbols mod_alias.erlmod_auth.erlmod_cgi.erlscript_aliasScriptAliasDocumentRootlib/inets/src/http_server/mod_alias.erllib/inets/src/http_server/mod_auth.erllib/inets/src/http_server/mod_cgi.erl

Keywords CVE-2026-28808Erlang OTP inets authentication bypassscript_alias CGI auth bypassmod_auth mod_cgi path mismatchinets httpd CGI bypassGHSA-3vhp-h532-mc3fErlang inets incorrect authorizationmod_alias mod_auth directory rules bypassOTP inets CGI unauthenticated accessEEF-CVE-2026-28808

Versions: OTP 17.0 to OTP 28.4.2 / 27.3.4.10 / 26.2.5.19 (inets 5.10 to 9.6.2 / 9.3.2.4 / 9.1.0.6)

References

Status: enriched · ingested 2026-06-30T06:00:22.000Z · profiled 2026-07-01T06:30:14.000Z