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CVE-2026-4224

Stack overflow parsing XML with deeply nested DTD content models

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 3.10.21, 3.11.16, 3.12.14, 3.13.13, 3.14.4, and 1 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

When an Expat parser with a registered ElementDeclHandler parses an inline document type definition containing a deeply nested content model a C stack overflow occurs.

Timeline

  1. CVE published
  2. CISA SSVC assessment

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

  3. Record last updated

Affected versions

  • Python Software Foundation CPython

    fixed in 3.10.21; From 3.11.0 · fixed in 3.11.16; From 3.12.0 · fixed in 3.12.14; From 3.13.0 · fixed in 3.13.13; From 3.14.0 · fixed in 3.14.4; From 3.15.0a1 · fixed in 3.15.0a8

References 9

GitHub · python/cpython

mail.python.org