DirectorySecurity AdvisoriesPricing
Sign in
Security Advisories

CVE-2026-34230

NVD

https://nvd.nist.gov/vuln/detail/CVE-2026-34230

Severity

5.3

Medium

CVSS V3

Eliminate CVEs with Chainguard hardened images

Build, ship, and run secure software with minimal, hardened container images — rebuilt from source daily and guarded under our industry-leading remediation SLA.

Start for free

Summary

Rack: Quadratic complexity in Rack::Utils.select_best_encoding via wildcard Accept-Encoding header

Description

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Utils.select_best_encoding processes Accept-Encoding values with quadratic time complexity when the header contains many wildcard (*) entries. Because this method is used by Rack::Deflater to choose a response encoding, an unauthenticated attacker can send a single request with a crafted Accept-Encoding header and cause disproportionate CPU consumption on the compression middleware path. This results in a denial of service condition for applications using Rack::Deflater. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.

References

  • https://nvd.nist.gov/vuln/detail/CVE-2026-34230
  • https://github.com/advisories/GHSA-v569-hp3g-36wr
  • https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34230.json
  • https://github.com/rack/rack/security/advisories/GHSA-v569-hp3g-36wr

Affected packages

The trusted source for open source

Talk to an expert
PrivacyTerms

Product

Chainguard ContainersChainguard LibrariesChainguard VMsChainguard OS PackagesChainguard ActionsChainguard Agent SkillsIntegrationsPricing

Solutions

FedRAMPPCI DSSCMMC 2.0SOC 2Golden ImagesCVE RemediationPublic SectorStartups

Customers

Customer StoriesChainguard Reviews

Resources

Events & WebinarsSupply Chain Security 101Chainguard CoursesDocumentationTrust CenterChainguard Slack Community

Company

About UsBlogOpen Source LeadershipPartnersNewsroomCareersLegal
© 2026 Chainguard, Inc. All Rights Reserved.
Chainguard® and the Chainguard logo are registered trademarks of Chainguard, Inc. in the United States and/or other countries.
The other respective trademarks mentioned on this page are owned by the respective companies and use of them does not imply any affiliation or endorsement.