CVE-2026-28808

CVE-2026-28808 is a critical-severity vulnerability in Erlang Erlang/inets with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-863.

Key facts

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.

Frequently asked questions

What is 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 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.
How severe is CVE-2026-28808?
CVE-2026-28808 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-28808 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-28808?
CVE-2026-28808 primarily affects Erlang Erlang/inets. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-28808?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-28808 have an EU (EUVD) identifier?
Yes. CVE-2026-28808 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-19602.
When was CVE-2026-28808 published?
CVE-2026-28808 was published on 2026-04-07 and last updated on 2026-06-30.

References

Affected products (2)

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