Critical severity · published Apr 7, 2026
CVE-2026-28808
ScriptAlias CGI targets bypass directory auth in inets httpd (mod_auth vs mod_cgi path mismatch)
9.8
CVSS
0.6%
EPSS
No
On KEV
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 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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 46% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OT
OTP · Erlang
17.0; 5.10; 07b8f441ca711f9812fad9e9115bab3c3aa92f79 · source: vendor
ER
Erlang/inets · Erlang
5.10 before 9.1.0.6; after 9.2 before 9.3.2.4; after 9.4 before 9.6.2 · source: NVD
ER
Erlang/otp · Erlang
17.0 before 26.2.5.19; 27.0 before 27.3.4.10; 28.0 before 28.4.2 · source: NVD
RH
Red Hat OpenStack Platform 16.2 · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat OpenStack Platform 17.1 · Red Hat
All versions, or not specified · source: CISA
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-28808
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-28808
Mitigation
https://cna.erlef.org/cves/CVE-2026-28808.html
github.com
https://github.com/erlang/otp/commit/07b8f441ca711f9812fad9e9115bab3c3aa92f79
Patch
https://github.com/erlang/otp/commit/8fc71ac6af4fbcc54103bec2983ef22e82942688
Patch
https://github.com/erlang/otp/commit/9dfa0c51eac97866078e808dec2183cb7871ff7c
Third Party Advisory
https://github.com/erlang/otp/security/advisories/GHSA-3vhp-h532-mc3f
Patch
https://osv.dev/vulnerability/EEF-CVE-2026-28808
More from OTP
10.0
CVE-2025-32433
Erlang/OTP SSH Vulnerable to Pre-Authentication RCE
9.8
CVE-2022-37026
In Erlang/OTP before 23.3.4.15, 24.x before 24.3.4.2, and 25.x before 25.0.2, there is a Client Authentication Bypass in certain client-certification situations for SSL, TLS, and…
9.8
CVE-2016-10253
An issue was discovered in Erlang/OTP 18.x
9.4
CVE-2026-23941
Request smuggling via first-wins Content-Length parsing in inets httpd
9.3
CVE-2026-89422
TLS 1.3 client skips server authentication when ServerHello carries an unsolicited pre_shared_key extension
