CVE-2026-0864 PUBLISHED

When using the "configparser" module to write configuration files containing multi-line text values with carriage return characters (\r) the resulting file could be injected with unexpected keys and values if the attacker controls the written value.

• D0n9 (https://github.com/D0n9) reporter
• Petr Viktorin (https://github.com/encukou) remediation reviewer
• Seth Larson (https://github.com/sethmlarson) coordinator

• https://github.com/python/cpython/pull/151559
• https://mail.python.org/archives/list/security-announce@python.org/thread/CV4NE6AFCRJL7XQOHX7J5TSDHUWVWGJS/
• https://github.com/python/cpython/issues/143927
• https://github.com/python/cpython/commit/5858e42c539dac8394636a6e9b30472b8994851f
• https://github.com/python/cpython/commit/0adb386f6e68eb2e73d32e19f235d012df009528
• https://github.com/python/cpython/commit/71f2e02a52d47417a6fd69f456346cd8aa7aca98
• https://github.com/python/cpython/commit/aaf850fd333cd89e9aada03d92aaa788a6cb1bb8