Erlang Erlang\/Inets
CVE-2026-28808
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.
What this means for your business
- It affects Erlang\/Inets. It matters if your company, or a supplier that handles your data, runs it.
- An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 0.6% chance of attack attempts being seen in the next 30 days, ranking above 44% of all known flaws.
What to do
- 1Check whether your company or your suppliers run Erlang\/Inets, and which version. The affected versions are listed further down this page.
- 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.
Not sure if your company is exposed?
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Scoring
- CVSS
- 9.8 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- CVSS v4
- 8.3
- Weakness
- CWE-863
- Assigned by
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Dates
- Published
- 2026-04-07
- Last modified
- 2026-09-08
- Sources
- NVD
Affected products
- Erlang Erlang\/Inets5.10 - 9.1.0.6, 9.2 - 9.3.2.4, 9.4 - 9.6.2
- Erlang Erlang\/Otp17.0 - 26.2.5.19, 27.0 - 27.3.4.10, 28.0 - 28.4.2
As listed in the NVD configuration data. Not a statement about your estate.
References
- https://cna.erlef.org/cves/CVE-2026-28808.html
- https://github.com/erlang/otp/commit/07b8f441ca711f9812fad9e9115bab3c3aa92f79
- https://github.com/erlang/otp/commit/8fc71ac6af4fbcc54103bec2983ef22e82942688
- https://github.com/erlang/otp/commit/9dfa0c51eac97866078e808dec2183cb7871ff7c
- https://github.com/erlang/otp/security/advisories/GHSA-3vhp-h532-mc3f
- https://osv.dev/vulnerability/EEF-CVE-2026-28808
- https://www.erlang.org/doc/system/versions.html#order-of-versions
- https://access.redhat.com/security/cve/CVE-2026-28808
- https://bugzilla.redhat.com/show_bug.cgi?id=2455909
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-28808.json