CVE-2026-32762
Description
Rack is a modular Ruby web server interface. From versions 3.0.0.beta1 to before 3.1.21 and 3.2.0 to before 3.2.6, Rack::Utils.forwarded_values parses the RFC 7239 Forwarded header by splitting on semicolons before handling quoted-string values. Because quoted values may legally contain semicolons, a header can be interpreted by Rack as multiple Forwarded directives rather than as a single quoted for value. In deployments where an upstream proxy, WAF, or intermediary validates or preserves quoted Forwarded values differently, this discrepancy can allow an attacker to smuggle host, proto, for, or by parameters through a single header value. This issue has been patched in versions 3.1.21 and 3.2.6.
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LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
rackRubyGems | >= 3.0.0.beta1, < 3.1.21 | 3.1.21 |
rackRubyGems | >= 3.2.0, < 3.2.6 | 3.2.6 |
Affected products
38- osv-coords37 versionspkg:apk/chainguard/kube-fluentd-operatorpkg:apk/chainguard/logstash-8.19pkg:apk/chainguard/logstash-8.19-iamguarded-compatpkg:apk/chainguard/logstash-8.19-with-output-opensearchpkg:apk/chainguard/logstash-9.0pkg:apk/chainguard/logstash-9.0-iamguarded-compatpkg:apk/chainguard/logstash-9.0-with-output-opensearchpkg:apk/chainguard/logstash-9.1pkg:apk/chainguard/logstash-9.1-bitnami-compatpkg:apk/chainguard/logstash-9.1-iamguarded-compatpkg:apk/chainguard/logstash-9.1-with-output-opensearchpkg:apk/chainguard/logstash-9.2pkg:apk/chainguard/logstash-9.2-iamguarded-compatpkg:apk/chainguard/logstash-9.2-with-output-opensearchpkg:apk/chainguard/logstash-9.3pkg:apk/chainguard/logstash-9.3-iamguarded-compatpkg:apk/chainguard/logstash-9.3-with-output-opensearchpkg:apk/chainguard/pact-broker-dockerpkg:apk/chainguard/pact-broker-docker-fipspkg:apk/chainguard/ruby3.2-rails-7.2pkg:apk/chainguard/ruby3.2-rails-8.0pkg:apk/chainguard/ruby3.4-rails-7.2pkg:apk/chainguard/ruby3.4-rails-8.0pkg:apk/wolfi/kube-fluentd-operatorpkg:apk/wolfi/logstash-9.1pkg:apk/wolfi/logstash-9.1-bitnami-compatpkg:apk/wolfi/logstash-9.1-iamguarded-compatpkg:apk/wolfi/logstash-9.1-with-output-opensearchpkg:apk/wolfi/logstash-9.2pkg:apk/wolfi/logstash-9.2-iamguarded-compatpkg:apk/wolfi/logstash-9.2-with-output-opensearchpkg:apk/wolfi/logstash-9.3pkg:apk/wolfi/logstash-9.3-iamguarded-compatpkg:apk/wolfi/logstash-9.3-with-output-opensearchpkg:apk/wolfi/ruby3.2-rails-8.0pkg:apk/wolfi/ruby3.4-rails-8.0pkg:gem/rack
< 1.18.2-r67+ 36 more
- (no CPE)range: < 1.18.2-r67
- (no CPE)range: < 8.19.14-r3
- (no CPE)range: < 8.19.14-r3
- (no CPE)range: < 8.19.14-r3
- (no CPE)range: < 9.0.8-r20
- (no CPE)range: < 9.0.8-r20
- (no CPE)range: < 9.0.8-r20
- (no CPE)range: < 9.1.10-r6
- (no CPE)range: < 9.1.10-r6
- (no CPE)range: < 9.1.10-r6
- (no CPE)range: < 9.1.10-r6
- (no CPE)range: < 9.2.8-r2
- (no CPE)range: < 9.2.8-r2
- (no CPE)range: < 9.2.8-r2
- (no CPE)range: < 9.3.3-r2
- (no CPE)range: < 9.3.3-r2
- (no CPE)range: < 9.3.3-r2
- (no CPE)range: < 2.137.0.2.118.0-r4
- (no CPE)range: < 2.137.0.2.118.0-r2
- (no CPE)range: < 7.2.3.1-r2
- (no CPE)range: < 8.0.5-r0
- (no CPE)range: < 7.2.3.1-r1
- (no CPE)range: < 8.0.5-r2
- (no CPE)range: < 1.18.2-r67
- (no CPE)range: < 9.1.10-r6
- (no CPE)range: < 9.1.10-r6
- (no CPE)range: < 9.1.10-r6
- (no CPE)range: < 9.1.10-r6
- (no CPE)range: < 9.2.8-r2
- (no CPE)range: < 9.2.8-r2
- (no CPE)range: < 9.2.8-r2
- (no CPE)range: < 9.3.3-r2
- (no CPE)range: < 9.3.3-r2
- (no CPE)range: < 9.3.3-r2
- (no CPE)range: < 8.0.5-r0
- (no CPE)range: < 8.0.5-r2
- (no CPE)range: >= 3.0.0.beta1, < 3.1.21
Patches
Vulnerability mechanics
References
4- github.com/advisories/GHSA-qfgr-crr9-7r49ghsaADVISORY
- github.com/rack/rack/security/advisories/GHSA-qfgr-crr9-7r49nvdVendor AdvisoryMitigationWEB
- nvd.nist.gov/vuln/detail/CVE-2026-32762ghsaADVISORY
- github.com/rubysec/ruby-advisory-db/blob/master/gems/rack/CVE-2026-32762.ymlghsaWEB
News mentions
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