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.
Published: 2026-04-07
Score: 8.3 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

No analysis available yet.

Remediation

Vendor Workaround

* Move CGI scripts inside DocumentRoot and use alias instead of script_alias to ensure mod_auth resolves the correct path. * Apply URL-based access controls at a reverse proxy layer to block unauthenticated access to the script_alias URL prefix. * Remove mod_cgi from the httpd modules chain if CGI functionality is not required.

Tracking

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Advisories

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History

Tue, 07 Apr 2026 15:15:00 +0000

Type Values Removed Values Added
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.
Title ScriptAlias CGI targets bypass directory auth in inets httpd (mod_auth vs mod_cgi path mismatch)
First Time appeared Erlang
Erlang erlang\/otp
Weaknesses CWE-863
CPEs cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:*
Vendors & Products Erlang
Erlang erlang\/otp
References
Metrics cvssV4_0

{'score': 8.3, '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'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Subscriptions

Erlang Erlang\/otp
cve-icon MITRE

Status: PUBLISHED

Assigner: EEF

Published:

Updated: 2026-04-07T14:38:09.190Z

Reserved: 2026-03-03T14:40:00.590Z

Link: CVE-2026-28808

cve-icon Vulnrichment

Updated: 2026-04-07T13:14:12.725Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-04-07T13:16:46.320

Modified: 2026-04-07T13:20:11.643

Link: CVE-2026-28808

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses