Erlang OTP up to 28.4.2 mod_alias.erl script_alias authorization

Summaryinfo

A vulnerability was found in Erlang OTP up to 28.4.2. It has been declared as critical. This vulnerability affects the function script_alias in the library lib/inets/src/http_server/mod_alias.erl. Executing a manipulation can lead to authorization. This vulnerability is tracked as CVE-2026-28808. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability was found in Erlang OTP up to 28.4.2. It has been declared as critical. This vulnerability affects the function script_alias in the library lib/inets/src/http_server/mod_alias.erl. The manipulation with an unknown input leads to a authorization vulnerability. The CWE definition for the vulnerability is CWE-863. The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-28808 since 03/03/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 07/02/2026).

The vulnerability scanner Nessus provides a plugin with the ID 305625 (Linux Distros Unpatched Vulnerability : CVE-2026-28808), which helps to determine the existence of the flaw in a target environment.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the databases at Tenable (305625) and CERT Bund (WID-SEC-2026-0998). Once again VulDB remains the best source for vulnerability data.

Affected

• SUSE openSUSE
• Microsoft Azure Linux
• Open Source Erlang/OTP

Productinfo

Vendor

• Erlang

Name

• OTP

Version

• 9.1.0.0
• 9.1.0.1
• 9.1.0.2
• 9.1.0.3
• 9.1.0.4
• 9.1.0.5
• 9.1.0.6
• 9.3.2.0
• 9.3.2.1
• 9.3.2.2
• 9.3.2.3
• 9.3.2.4
• 9.6.0
• 9.6.1
• 9.6.2
• 17.0
• 26.2.5.0
• 26.2.5.1
• 26.2.5.2
• 26.2.5.3
• 26.2.5.4
• 26.2.5.5
• 26.2.5.6
• 26.2.5.7
• 26.2.5.8
• 26.2.5.9
• 26.2.5.10
• 26.2.5.11
• 26.2.5.12
• 26.2.5.13
• 26.2.5.14
• 26.2.5.15
• 26.2.5.16
• 26.2.5.17
• 26.2.5.18
• 26.2.5.19
• 27.3.4.0
• 27.3.4.1
• 27.3.4.2
• 27.3.4.3
• 27.3.4.4
• 27.3.4.5
• 27.3.4.6
• 27.3.4.7
• 27.3.4.8
• 27.3.4.9
• 27.3.4.10
• 28.4.0
• 28.4.1
• 28.4.2

Website

• Product: https://github.com/erlang/otp/

CPE 2.3info

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CPE 2.2info

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Entryinfo

Once again VulDB remains the best source for vulnerability data.

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