CVE-2023-28846 — Unpoly is a JavaScript framework for server-side web applications

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 upst

01What is this vulnerability?

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…

02Affected products

Vendor	Product	Versions
unpoly	unpoly	rails — < 2.7.2.2

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2023-03-30T19:57:38.767Z
• Last modified: 2025-02-11T18:46:42.157Z

09References

• github.com — https://github.com/unpoly/unpoly-rails/security/advisories/GHSA-m875-3xf6-mf78
• github.com — https://github.com/unpoly/unpoly-rails/commit/cd9ad0007daceeb3b2354fdcab4f883504…
• docs.nginx.com — https://docs.nginx.com/nginx/admin-guide/load-balancer/http-health-check/#passiv…
• github.com — https://github.com/unpoly/unpoly-rails/
• makandracards.com — https://makandracards.com/operations/537537-nginx-proxy-buffer-tuning
• tryhexadecimal.com — https://tryhexadecimal.com/guides/http/414-request-uri-too-long
• unpoly.com — https://unpoly.com/up.protocol