PSF-2026-8

The record

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".

Affected packages

Related vulnerabilities

• CVE-2026-1299 The email module, specifically the "BytesGenerator" class, didn’t properly quote newlines… Same vulnerability
• CVE-2025-12781 When passing data to the b64decode(), standard_b64decode(), and urlsafe_b64decode()… Also affects libpython
• PSF-2026-7 When passing data to the b64decode(), standard_b64decode(), and urlsafe_b64decode()… Also affects libpython
• CVE-2026-0672 When using http.cookies.Morsel, user-controlled cookie values and parameters can allow… Also affects libpython
• CVE-2026-0865 User-controlled header names and values containing newlines can allow injecting HTTP… Also affects libpython
• CVE-2025-15367 The poplib module, when passed a user-controlled command, can have additional commands… Also affects libpython
• CVE-2025-15366 The imaplib module, when passed a user-controlled command, can have additional commands… Also affects libpython
• CVE-2025-11468 When folding a long comment in an email header containing exclusively unfoldable… Also affects libpython