ScriptAlias CGI targets bypass directory auth in inets httpd (mod_auth vs mod_cgi path mismatch)
Summary
| CVE | CVE-2026-28808 |
|---|---|
| State | PUBLISHED |
| Assigner | EEF |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-04-07 13:16:46 UTC |
| Updated | 2026-07-15 02:19:16 UTC |
| 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. |
Risk And Classification
Primary CVSS: v4.0 8.3 HIGH from 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Problem Types: CWE-863 | CWE-551 | CWE-863 CWE-863 Incorrect Authorization | CWE-551 Incorrect Behavior Order: Authorization Before Parsing and Canonicalization
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | Secondary | 8.3 | HIGH | 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/E:X/C... |
| 4.0 | CNA | CVSS | 8.3 | HIGH | 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 |
| 3.1 | [email protected] | Primary | 9.8 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| 3.1 | ADP | CVSS | 7.4 | HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
| 3.1 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | Secondary | 7.4 | HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
CVSS v4.0 Breakdown
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS v3.1 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Application | Erlang | Erlang/inets | All | All | All | All |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Erlang | OTP | affected 5.10 * otp | Not specified |
| CNA | Erlang | OTP | affected 17.0 * otp | Not specified |
| CNA | Erlang | OTP | affected 07b8f441ca711f9812fad9e9115bab3c3aa92f79 * git | Not specified |
| ADP | Red Hat | Red Hat OpenStack Platform 16.2 | Not specified | Not specified |
| ADP | Red Hat | Red Hat OpenStack Platform 17.1 | Not specified | Not specified |
| ADP | Red Hat | Red Hat OpenStack Platform 18.0 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| bugzilla.redhat.com/show_bug.cgi | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | bugzilla.redhat.com | |
| cna.erlef.org/cves/CVE-2026-28808.html | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | cna.erlef.org | Mitigation, Vendor Advisory |
| access.redhat.com/security/cve/CVE-2026-28808 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| github.com/erlang/otp/commit/9dfa0c51eac97866078e808dec2183cb7871ff7c | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | github.com | Patch |
| www.erlang.org/doc/system/versions.html | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | www.erlang.org | Product |
| osv.dev/vulnerability/EEF-CVE-2026-28808 | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | osv.dev | Patch, Third Party Advisory |
| security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-28808.json | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | security.access.redhat.com | |
| github.com/erlang/otp/security/advisories/GHSA-3vhp-h532-mc3f | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | github.com | Third Party Advisory |
| github.com/erlang/otp/commit/8fc71ac6af4fbcc54103bec2983ef22e82942688 | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | github.com | Patch |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Igor Morgenstern / Aisle Research (en)
CNA: Konrad Pietrzak (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| ADP | 2026-04-07T13:01:42.326Z | Reported to Red Hat. |
| ADP | 2026-04-07T12:28:16.056Z | Made public. |
Workarounds
CNA: * 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.
ADP: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.