CRITICAL: CVE-2026-28808 (CVSS 9.8) — erlang erlang\/inets

CVE: CVE-2026-28808

CVSS: 9.8 (3.1) — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity: CRITICAL

Status: Critical advisory

Affected

• erlang erlang\/inets
• erlang erlang\/otp

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 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.

Verified Sources

• NVD entry
• GitHub Advisory
• MITRE

References

• https://cna.erlef.org/cves/CVE-2026-28808.html
• 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

_Validated by the Lyrie Threat Intelligence Pipeline — 3 independent sources confirmed before publication. No speculation._