---
id: CVE-2026-73270
title: >-
  Improper Handling of Case Sensitivity vulnerability in Erlang/OTP inets httpd
  allows a remote unauthenticated attacker to read files inside a mod_auth
  protected directory by requesting them with different casing, on deployments
  whose fil…
summary: >-
  Improper Handling of Case Sensitivity vulnerability in Erlang/OTP inets httpd
  allows a remote unauthenticated attacker to read files inside a mod_auth
  protected directory by requesting them with different casing, on deployments
  whose fil…
severity: high
cvss: 8.2
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'
cwe:
  - CWE-178
vendor: Erlang
product: otp
affected:
  - otp >= 17.0 < 27.3.4.17
  - otp >= 28.0 < 28.5.0.6
  - otp >= 29.0 < 29.0.6
  - inets >= 5.10 < 9.3.2.7
  - inets >= 9.4 < 9.6.2.3
  - inets >= 9.7 < 9.7.2
  - erlang/otp >= 84adefa331c4159d432d22840663c38f155cd4c1 < *
published: '2026-09-01'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T01:17:53.753'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73270'
references:
  - url: 'https://cna.erlef.org/cves/CVE-2026-73270.html'
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/erlang/otp/commit/9641944a2efbf55bea760f8ff7ba777fe3a0961c
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/erlang/otp/commit/bac19eb3dbd96cc49b6d8cabc1c04248bf8c79f6
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/erlang/otp/commit/d8878dec0ececc2eab18e47bb18b472f224ca633
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: 'https://github.com/erlang/otp/security/advisories/GHSA-mh78-93cr-jx8f'
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: 'https://osv.dev/vulnerability/EEF-CVE-2026-73270'
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: 'https://www.erlang.org/doc/system/versions.html#order-of-versions'
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-01T15:58:36.382951Z'
cvssSource: cna
epss: 0.00927
epssPercentile: 0.5881
ingestedAt: '2026-09-08T15:33:26.956Z'
---

## Overview

Improper Handling of Case Sensitivity vulnerability in Erlang/OTP inets httpd allows a remote unauthenticated attacker to read files inside a mod_auth protected directory by requesting them with different casing, on deployments whose filesystem is case-insensitive.

mod_auth:secret_path/3 decides whether a resolved filesystem path lies inside a protected directory block by running the configured directory path through re:run/3 without the caseless option. A request for /secret/file against a directory configured as /Secret therefore does not match, so the request is treated as unprotected and no authentication challenge is issued, while the filesystem resolves the differently cased path to the same file and mod_get serves it. Deployments on case-sensitive filesystems are unaffected, because there the filesystem itself rejects the mismatched casing.

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.