Vulnerability Details : CVE-2023-28846
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.
Vulnerability category: Denial of service
Products affected by CVE-2023-28846
- cpe:2.3:a:unpoly:unpoly-rails:*:*:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2023-28846
0.42%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 75 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2023-28846
Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
---|---|---|---|---|---|---|
7.5
|
HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
3.9
|
3.6
|
NIST | |
5.9
|
MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H |
2.2
|
3.6
|
GitHub, Inc. |
CWE ids for CVE-2023-28846
-
The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.Assigned by: security-advisories@github.com (Primary)
References for CVE-2023-28846
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https://makandracards.com/operations/537537-nginx-proxy-buffer-tuning
Nginx Proxy buffer tuning - makandra OperationsThird Party Advisory
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https://github.com/unpoly/unpoly-rails/security/advisories/GHSA-m875-3xf6-mf78
Possible Denial of Service in unpoly-rails · Advisory · unpoly/unpoly-rails · GitHubVendor Advisory
-
https://github.com/unpoly/unpoly-rails/
GitHub - unpoly/unpoly-rails: Ruby on Rails bindings for UnpolyProduct
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https://tryhexadecimal.com/guides/http/414-request-uri-too-long
414 Request-URI Too Long - HexadecimalThird Party Advisory
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https://docs.nginx.com/nginx/admin-guide/load-balancer/http-health-check/#passive-health-checks
HTTP Health Checks | NGINX PlusTechnical Description
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https://github.com/unpoly/unpoly-rails/commit/cd9ad0007daceeb3b2354fdcab4f88350427bf16
Only echo the request URL as X-Up-Location if it contains query param… · unpoly/unpoly-rails@cd9ad00 · GitHubPatch;Vendor Advisory
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https://unpoly.com/up.protocol
Server protocol - UnpolyProduct
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