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Description

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.

Affected products

VendorProductAffectedFixed
rack rack < 2.2.23, >= 3.0.0.beta1, < 3.1.21, >= 3.2.0, < 3.2.6 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 ruby-rack 3.2.6-2 —
Debian 13 ruby-rack 3.1.20-0+deb13u2 —
Debian 12 ruby-rack 2.2.22-0+deb12u2 —
ReleasePackageFixed inAdvisory
Ubuntu 26.04 LTS ruby-rack 3.2.4-1ubuntu1.1 USN-8989-1
Ubuntu 25.10 ruby-rack 3.1.16-0.1ubuntu0.3 —
Ubuntu 24.04 LTS ruby-rack 2.2.7-1ubuntu0.7 —
Show 4 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu Pro 22.04 LTS ruby-rack 2.1.4-5ubuntu1.2+esm3 —
Ubuntu Pro 18.04 LTS ruby-rack 1.6.4-4ubuntu0.2+esm10 —
Ubuntu Pro 16.04 LTS ruby-rack No fix yet —
Ubuntu Pro 14.04 LTS ruby-rack No fix yet —
ReleasePackageFixed inAdvisory
SLES 15 SP6 rmt-server 2.27-150500.3.47.1 SUSE-SU-2026:2487-1
SLES 15 SP5 rmt-server 2.27-150500.3.47.1 SUSE-SU-2026:2487-1
Show 5 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLES for SAP 16.0 rmt-server 3.1.0-160000.1.1 SUSE-SU-2026:23321-1
SLES for SAP 15 SP6 rmt-server 2.27-150500.3.47.1 SUSE-SU-2026:2487-1
SLES for SAP 15 SP5 rmt-server 2.27-150500.3.47.1 SUSE-SU-2026:2487-1
SLES 16.0 rmt-server 3.1.0-160000.1.1 SUSE-SU-2026:23321-1
SLE HPC 15 SP5 rmt-server 2.27-150500.3.47.1 SUSE-SU-2026:2487-1
ReleasePackageFixed inAdvisory
openSUSE Tumbleweed rubygem-rack-2.2 2.2.23-1.1 openSUSE-SU-2026:10508-1
openSUSE Leap 16.0 rmt-server 3.1.0-160000.1.1 openSUSE-SU-2026:21640-1

Wolfi

ReleasePackageFixed inAdvisory
Wolfi rolling kube-fluentd-operator 1.18.2-r60 —
Wolfi rolling logstash-9.3 +2 9.3.3-r2 —
Wolfi rolling ruby3.2-rack-2.2 +2 2.2.23-r0 —
Wolfi rolling ruby3.3-rack-2.2 2.2.22-r0 —

Affected packages

EcosystemPackageAffectedFixedRecord
RubyGems rack < 2.2.23 2.2.23 GHSA-q4qf-9j86-f5mh
RubyGems rack >= 3.0.0.beta1, < 3.1.21 3.1.21 GHSA-q4qf-9j86-f5mh
RubyGems rack >= 3.2.0, < 3.2.6 3.2.6 GHSA-q4qf-9j86-f5mh

Advisories 6

References