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EEF-CVE-2026-28808

HighCVSS 8.3 / 10
Published Apr 7, 2026·Last modified Sep 8, 2026
Affected Components(50)
erlang/otp
OTP-27.3.4
erlang/otp
OTP-27.0
erlang/otp
patch-base-26
1 / 17
Description

Summary

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.

Workarounds

  • 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.

Configurations

The inets httpd server must use script_alias to map a URL prefix to a CGI directory, combined with directory-based access controls (e.g., mod_auth) protecting the script_alias target path. The vulnerability applies whenever the script_alias target path differs from DocumentRoot + URL prefix.

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Risk Scores
Base Score
8.3

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability.

Threat Intelligence
4.8

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
N/A

Probability that this vulnerability will be exploited in the wild within the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

Related Vulnerabilities
  • CVE-2026-28808
    Alias
  • EUVD-2026-19602
    Alias

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High severity
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