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CVE-2026-42874PYSEC-2026-2646GHSA-7WC8-WVC4-M498

Microdot: HTTP response splitting in Response.set_cookie()

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 2.6.1
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

Microdot is a minimalistic Python web framework. Prior to 2.6.1, the Response.set_cookie() method does not sanitize its string arguments, and in particular will not detect the presence of the \r\n sequence in them. This can be a potential source of header injection attacks. For a header injection attack through this issue to be possible, an attacker must first infiltrate the client (for example through an independent XSS attack), so that it can send malicious information that is destined to be stored in a cookie by the server on behalf of the victim. An attacker that infiltrates one client can only orchestrate a header injection attack for that client, all other clients that were not infiltrated are safe. This vulnerability is fixed in 2.6.1.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • miguelgrinberg microdot

    fixed in 2.6.1

  • microdotPyPI

    fixed in 2.6.1

References 3

GitHub · miguelgrinberg/microdot