CVE-2026-28808

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 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.

CVSS breakdown

Affected products

• erlang / erlang/otp

References

• VENDOR_ADVISORYhttps://github.com/erlang/otp/security/advisories/GHSA-3vhp-h532-mc3f
• MISChttps://cna.erlef.org/cves/CVE-2026-28808.html
• MISChttps://osv.dev/vulnerability/EEF-CVE-2026-28808
• MISChttps://www.erlang.org/doc/system/versions.html#order-of-versions
• PATCHhttps://github.com/erlang/otp/commit/8fc71ac6af4fbcc54103bec2983ef22e82942688
• PATCHhttps://github.com/erlang/otp/commit/9dfa0c51eac97866078e808dec2183cb7871ff7c