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Security Advisories

CVE-2026-26962

NVD

https://nvd.nist.gov/vuln/detail/CVE-2026-26962

Severity

4.8

Medium

CVSS V3

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Summary

Rack: Header injection in multipart requests

Description

Rack is a modular Ruby web server interface. From version 3.2.0 to before version 3.2.6, Rack::Multipart::Parser unfolds folded multipart part headers incorrectly. When a multipart header contains an obs-fold sequence, Rack preserves the embedded CRLF in parsed parameter values such as filename or name instead of removing the folded line break during unfolding. As a result, applications that later reuse those parsed values in HTTP response headers may be vulnerable to downstream header injection or response splitting. This issue has been patched in version 3.2.6.

References

  • https://nvd.nist.gov/vuln/detail/CVE-2026-26962
  • https://github.com/advisories/GHSA-rx22-g9mx-qrhv
  • https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/26xxx/CVE-2026-26962.json
  • https://github.com/rack/rack/security/advisories/GHSA-rx22-g9mx-qrhv

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