CVE-2026-34830
Last modified
CVE-2026-34830 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Sendfile#map_accel_path interpolates the value of the X-Accel-Mapping request header directly into a regular expression when rewriting file paths for X-Accel-Redirect. EPSS estimates a 0.21% chance of exploitation in the next 30 days.
Description
Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Sendfile#map_accel_path interpolates the value of the X-Accel-Mapping request header directly into a regular expression when rewriting file paths for X-Accel-Redirect. Because the header value is not escaped, an attacker who can supply X-Accel-Mapping to the backend can inject regex metacharacters and control the generated X-Accel-Redirect response header. In deployments using Rack::Sendfile with x-accel-redirect, this can allow an attacker to cause nginx to serve unintended files from configured internal locations. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.
Metrics
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Rack | Rack | < 2.2.23 |
| Rack | Rack | >= 3.0.0, < 3.1.21 |
| Rack | Rack | >= 3.2.0, < 3.2.6 |
References
Timeline
- Published
- Last Modified
- Status
- Analyzed
Frequently Asked Questions
What is CVE-2026-34830?
How severe is CVE-2026-34830?
How do I fix CVE-2026-34830?
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
Related CVEs from 2026
- CVE-2026-34825NocoBase is an AI-powered no-code/low-code platform for buil…6.5
- CVE-2026-34826Rack is a modular Ruby web server interface. Prior to versio…7.5
- CVE-2026-34827Rack is a modular Ruby web server interface. From versions 3…7.5
- CVE-2026-34828listmonk is a standalone, self-hosted, newsletter and mailin…7.1
- CVE-2026-34829Rack is a modular Ruby web server interface. Prior to versio…7.5
- CVE-2026-3483An exposed dangerous method in Ivanti DSM before version 202…7.8
- CVE-2026-34831Rack is a modular Ruby web server interface. Prior to versio…6.5
- CVE-2026-34832Scoold is a Q&A and a knowledge sharing platform for teams. …6.5
- CVE-2026-34833Bulwark Webmail is a self-hosted webmail client for Stalwart…7.5
- CVE-2026-34834Bulwark Webmail is a self-hosted webmail client for Stalwart…7.5
- CVE-2026-34835Rack is a modular Ruby web server interface. From versions 3…6.5
- CVE-2026-34836Combodo iTop is a web based IT service management tool. Prio…6.5
Are you affected by CVE-2026-34830?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST