Path Equivalence vulnerability in Erlang/OTP inets httpd allows a remote unauthenticated attacker to read files inside a mod_auth protected directory by prefixing the request path with an extra slash. httpd_request:validate_uri/1 normalises the request URI with uri_string:normalize/1, which performs RFC 3986 dot-segment removal but does not collapse empty path segments, so a doubled slash survives. mod_alias:real_name/3 concatenates the document root with that URI, and mod_auth:secret_path/3 then decides whether the result lies inside a protected directory block by running the configured directory path as an unanchored regular expression against it. The doubled slash breaks the contiguous substring the regex needs, so the request is treated as unprotected and no authentication challenge is issued, while mod_get opens the same path and the operating system collapses the doubled slash and returns the protected file. The same path mismatch also evades the per-path accounting in mod_security. This issue affects OTP from OTP 17.0 before OTP 27.3.4.17, from OTP 28.0 before OTP 28.5.0.6, and from OTP 29.0 before OTP 29.0.6, corresponding to inets from 5.10 before 9.3.2.7, from 9.4 before 9.6.2.3, and from 9.7 before 9.7.2. Whether OTP before OTP 17.0, corresponding to inets before 5.10, is affected is unknown.

The remote Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8827-1 advisory.

    It was discovered that the Erlang Port Mapper Daemon did not properly handle slow connections. A remote     attacker could possibly use this issue to cause a denial of service. (CVE-2026-42792)

    It was discovered that Erlang incorrectly handled certain external term format data, leading to heap     corruption. An attacker could possibly use this issue to cause Erlang to crash, resulting in a denial of     service. This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-55737)

    It was discovered that Erlang incorrectly handled invalid external term format data. An attacker could     possibly use this issue to cause Erlang to crash, resulting in a denial of service. This issue only     affected Ubuntu 26.04 LTS. (CVE-2026-54890)

    It was discovered that Erlang incorrectly handled certain packet lengths, leading to a buffer overflow. A     remote attacker could possibly use this issue to cause Erlang to crash or execute arbitrary code.
    (CVE-2026-75538)

    It was discovered that the Erlang Megaco flex scanner incorrectly handled certain input, leading to a     buffer overflow. A remote attacker could possibly use this issue to cause Erlang to crash or execute     arbitrary code. (CVE-2026-59250)

    It was discovered that Erlang TLS clients incorrectly accepted cipher suites that they had not offered. A     remote attacker could possibly use this issue to intercept and modify TLS communications. (CVE-2026-55953)

    It was discovered that Erlang incorrectly handled certain certificate chains. A remote attacker could     possibly use this issue to cause Erlang to use excessive resources, leading to a denial of service. This     issue only affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS. (CVE-2026-58227)

    It was discovered that Erlang incorrectly handled certain certificate policies. A remote attacker could     possibly use this issue to cause Erlang to use excessive resources, leading to a denial of service. This     issue only affected Ubuntu 26.04 LTS. (CVE-2026-59251)

    It was discovered that the Erlang HTTP server incorrectly handled certain conflicting HTTP framing     headers. A remote attacker could possibly use this issue to smuggle HTTP requests. (CVE-2026-23941,     CVE-2026-73812)

    It was discovered that the Erlang HTTP server incorrectly handled certain malformed chunk sizes. A remote     attacker could possibly use this issue to cause Erlang to crash, resulting in a denial of service.
    (CVE-2026-69664)

    It was discovered that the Erlang HTTP server did not properly limit the size of chunked request bodies. A     remote attacker could possibly use this issue to cause Erlang to use excessive resources, leading to a     denial of service. (CVE-2026-74835)

    It was discovered that the Erlang HTTP server incorrectly handled certain equivalent request paths and     differences in character case. A remote attacker could possibly use this issue to bypass authentication     and gain unauthorized access. (CVE-2026-66835, CVE-2026-73270)

    It was discovered that the Erlang HTTP server did not properly limit simultaneous connections. A remote     attacker could possibly use this issue to cause Erlang to use excessive resources, leading to a denial of     service. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS,     Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS. (CVE-2026-70399)

    It was discovered that the Erlang HTTP server incorrectly handled header continuation lines. A remote     attacker could possibly use this issue to smuggle HTTP requests. (CVE-2026-66357)

    It was discovered that the Erlang HTTP server incorrectly handled certain malformed header names. A remote     attacker could possibly use this issue to smuggle HTTP requests. This issue only affected Ubuntu 20.04     LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS. (CVE-2026-73276)

    It was discovered that the Erlang HTTP server incorrectly handled incomplete request bodies. A remote     attacker could possibly use this issue to cause Erlang to use excessive resources, leading to a denial of     service. (CVE-2026-71380)

    It was discovered that the Erlang HTTP client did not properly limit the size of HTTP response headers. A     malicious HTTP server could possibly use this issue to cause Erlang to use excessive resources, leading to     a denial of service. (CVE-2026-55951)

    It was discovered that Erlang did not properly limit the length of port numbers when parsing URIs. A     remote attacker could possibly use this issue to cause Erlang to use excessive resources, leading to a     denial of service. This issue only affected Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and     Ubuntu 26.04 LTS. (CVE-2026-59696)

    It was discovered that the Erlang SNMP application did not properly limit the size of certain integer     values. A remote attacker could possibly use this issue to cause Erlang to use excessive resources,     leading to a denial of service. (CVE-2026-70405)

    It was discovered that the Erlang LDAP client did not properly limit the length of port numbers in     referral URLs. A malicious LDAP server could possibly use this issue to cause Erlang to use excessive     resources, leading to a denial of service. (CVE-2026-70409)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by multiple vulnerabilities as referenced in the e9dfc357-a63f-11f1-9195-4c526214c986 advisory.

    The Erlang/OTP project reports:
    OTP 29.0.6, 28.5.0.6 and 27.3.4.17 fix the following               issues, most of them in the inets httpd and httpc               implementations:

Tenable has extracted the preceding description block directly from the FreeBSD security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - Path Equivalence vulnerability in Erlang/OTP inets httpd allows a remote unauthenticated attacker to read     files inside a mod_auth protected directory by prefixing the request path with an extra slash.
    httpd_request:validate_uri/1 normalises the request URI with uri_string:normalize/1, which performs RFC     3986 dot-segment removal but does not collapse empty path segments, so a doubled slash survives.
    mod_alias:real_name/3 concatenates the document root with that URI, and mod_auth:secret_path/3 then     decides whether the result lies inside a protected directory block by running the configured directory     path as an unanchored regular expression against it. The doubled slash breaks the contiguous substring the     regex needs, so the request is treated as unprotected and no authentication challenge is issued, while     mod_get opens the same path and the operating system collapses the doubled slash and returns the protected     file. The same path mismatch also evades the per-path accounting in mod_security. This issue affects OTP     from OTP 17.0 before OTP 27.3.4.17, from OTP 28.0 before OTP 28.5.0.6, and from OTP 29.0 before OTP     29.0.6, corresponding to inets from 5.10 before 9.3.2.7, from 9.4 before 9.6.2.3, and from 9.7 before     9.7.2. Whether OTP before OTP 17.0, corresponding to inets before 5.10, is affected is unknown.
    (CVE-2026-66835)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
350965	Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS : Erlang vulnerabilities (USN-8827-1)	Nessus	Ubuntu Local Security Checks	Local	critical
342490	FreeBSD : Erlang/OTP -- multiple vulnerabilities in inets, stdlib, snmp and eldap (e9dfc357-a63f-11f1-9195-4c526214c986)	Nessus	FreeBSD Local Security Checks	Local	high
342478	Linux Distros Unpatched Vulnerability : CVE-2026-66835	Nessus	Misc.	Local	high

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