ruby-rack: Rack is a modular Ruby web server interface
CVE-2026-34786 is fixed in 2 products on 1 platform, first by ruby-rack 3.2.4-1ubuntu1.1, released April 2, 2026. It is not reported as exploited. Patch Radar priority: Routine.
Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Static#applicable_rules evaluates several header_rules types against the raw URL-encoded PATH_INFO, while the underlying file-serving path is decoded before the file is served. As a result, a request for a URL-encoded variant of a static path can serve the same file without the headers that header_rules were intended to apply. In deployments that rely on Rack::Static to attach security-relevant response headers to static content, this can allow an attacker to bypass those headers by requesting an encoded form of the path. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| rmt-server · opensuse-leap 16.0 | 3.1.0-160000.1.1 | OPENSUSE-SU-2026:21640-1 | Aug 25, 2026 |
| rmt-server · sles 15.6 | 2.27-150500.3.47.1 | SUSE-SU-2026:2487-1 | Jun 22, 2026 |
| rmt-server · sles 16.0 | 3.1.0-160000.1.1 | SUSE-SU-2026:23321-1 | Aug 25, 2026 |
| ruby-rack · Debian 12.15 (bookworm) | 2.2.22-0+deb12u2 | DEBIAN-CVE-2026-34786 | Apr 2, 2026 |
| ruby-rack · Debian 13.5 (trixie) | 3.1.20-0+deb13u2 | DEBIAN-CVE-2026-34786 | Apr 2, 2026 |
| ruby-rack · Debian 14 | 3.2.6-2 | DEBIAN-CVE-2026-34786 | Apr 2, 2026 |
| ruby-rack · Ubuntu 18.04.6 LTS (bionic) | 1.6.4-4ubuntu0.2+esm10 | ruby-rack 1.6.4-4ubuntu0.2+esm10 | Apr 30, 2026 |
| ruby-rack · Ubuntu 22.04.1 LTS (jammy) | 2.1.4-5ubuntu1.2+esm3 | ruby-rack 2.1.4-5ubuntu1.2+esm3 | Apr 30, 2026 |
| ruby-rack · Ubuntu 24.04.5 LTS (noble) | 2.2.7-1ubuntu0.7 | ruby-rack 2.2.7-1ubuntu0.7 | Apr 30, 2026 |
| ruby-rack · Ubuntu 25.10 (questing) | 3.1.16-0.1ubuntu0.3 | ruby-rack 3.1.16-0.1ubuntu0.3 | Apr 30, 2026 |
| ruby-rack · Ubuntu 26.04.1 LTS (resolute) | 3.2.4-1ubuntu1.1 | ruby-rack 3.2.4-1ubuntu1.1 | Apr 2, 2026 |
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