Advisory details:
github_osv / GHSA-2rqw-v265-jf8c
| Advisory ID | github_osv/GHSA-2rqw-v265-jf8c |
| Aliases |
CVE-2021-22942
|
| Summary | Open Redirect in ActionPack # Overview There is a possible open redirect vulnerability in the Host Authorization middleware in Action Pack. This vulnerability has been assigned the CVE identifier CVE-2021-22942. Versions Affected: >= 6.0.0. Not affected: < 6.0.0 Fixed Versions: 6.1.4.1, 6.0.4.1 # Impact Specially crafted “X-Forwarded-Host” headers in combination with certain “allowed host” formats can cause the Host Authorization middleware in Action Pack to redirect users to a malicious website. Impacted applications will have allowed hosts with a leading dot. For example, configuration files that look like this: ```ruby config.hosts << '.EXAMPLE.com' ``` When an allowed host contains a leading dot, a specially crafted Host header can be used to redirect to a malicious website. This vulnerability is similar to CVE-2021-22881, but CVE-2021-22881 did not take in to account domain name case sensitivity. # Releases The fixed releases are available at the normal locations. # Workarounds In the case a patch can’t be applied, the following monkey patch can be used in an initializer: ```ruby module ActionDispatch class HostAuthorization HOSTNAME = /[a-z0-9.-]+|\[[a-f0-9]*:[a-f0-9.:]+\]/i VALID_ORIGIN_HOST = /\A(#{HOSTNAME})(?::\d+)?\z/ VALID_FORWARDED_HOST = /(?:\A|,[ ]?)(#{HOSTNAME})(?::\d+)?\z/ private def authorized?(request) origin_host = request.get_header("HTTP_HOST")&.slice(VALID_ORIGIN_HOST, 1) || "" forwarded_host = request.x_forwarded_host&.slice(VALID_FORWARDED_HOST, 1) || "" @permissions.allows?(origin_host) && (forwarded_host.blank? || @permissions.allows?(forwarded_host)) end end end ``` |
| Status | Published |
| Exploitability | 0.5 |
| Weighted Severity | 5.5 |
| Risk | 2.8 |
| Affected and Fixed Packages | Package Details |
| Introduced and Fixed Package Commit Patches | Package Commit Patches Details |
| There are no known CWE. |
| System | Score | Found at |
|---|---|---|
| cvssv3.1 | 6.1 | https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/08/GHSA-2rqw-v265-jf8c/GHSA-2rqw-v265-jf8c.json |
| generic_textual | MODERATE |
No exploits are available.
No EPSS data available for this advisory.
| Patch URL | |
|---|---|
| There are no known patches. | |
| Attack Vector (AV) | Attack Complexity (AC) | Privileges Required (PR) | User Interaction (UI) | Scope (S) | Confidentiality Impact (C) | Integrity Impact (I) | Availability Impact (A) |
|---|---|---|---|---|---|---|---|
network adjacent_network local physical |
low high |
none low high |
none required |
unchanged changed |
high low none |
high low none |
high low none |
There are no SSVC decisions available.