CVE-2026-1299 PUBLISHED

The email module, specifically the "BytesGenerator" class, didn’t properly quote newlines for email headers when serializing an email message allowing for header injection when an email is serialized. This is only applicable if using "LiteralHeader" writing headers that don't respect email folding rules, the new behavior will reject the incorrectly folded headers in "BytesGenerator".

• https://github.com/python/cpython/pull/144126
• https://github.com/python/cpython/issues/144125
• https://cve.org/CVERecord?id=CVE-2024-6923
• https://mail.python.org/archives/list/security-announce@python.org/thread/6ZZULGALJTITEAGEXLDJE2C6FORDXPBT/
• https://github.com/python/cpython/commit/052e55e7d44718fe46cbba0ca995cb8fcc359413

• CWE-93 CWE