7.5 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
0.003 Low
EPSS
Percentile
68.6%
Unpoly is a JavaScript framework for server-side web applications. There is a possible Denial of Service (DoS) vulnerability in the unpoly-rails
gem that implements the Unpoly server protocol for Rails applications. This issues affects Rails applications that operate as an upstream of a load balancer’s that uses passive health checks. The unpoly-rails
gem echoes the request URL as an X-Up-Location
response header. By making a request with exceedingly long URLs (paths or query string), an attacker can cause unpoly-rails to write a exceedingly large response header. If the response header is too large to be parsed by a load balancer downstream of the Rails application, it may cause the load balancer to remove the upstream from a load balancing group. This causes that application instance to become unavailable until a configured timeout is reached or until an active healthcheck succeeds. This issue has been fixed and released as version 2.7.2.2 which is available via RubyGems and GitHub. Users unable to upgrade may: Configure your load balancer to use active health checks, e.g. by periodically requesting a route with a known response that indicates healthiness; Configure your load balancer so the maximum size of response headers is at least twice the maximum size of a URL; or instead of changing your server configuration you may also configure your Rails application to delete redundant X-Up-Location
headers set by unpoly-rails.
Vendor | Product | Version | CPE |
---|---|---|---|
unpoly | unpoly\-rails | * | cpe:2.3:a:unpoly:unpoly\-rails:*:*:*:*:*:*:*:* |
[
{
"vendor": "unpoly",
"product": "unpoly-rails",
"versions": [
{
"version": "< 2.7.2.2",
"status": "affected"
}
]
}
]
docs.nginx.com/nginx/admin-guide/load-balancer/http-health-check/#passive-health-checks
github.com/unpoly/unpoly-rails/
github.com/unpoly/unpoly-rails/commit/cd9ad0007daceeb3b2354fdcab4f88350427bf16
github.com/unpoly/unpoly-rails/security/advisories/GHSA-m875-3xf6-mf78
makandracards.com/operations/537537-nginx-proxy-buffer-tuning
tryhexadecimal.com/guides/http/414-request-uri-too-long
unpoly.com/up.protocol