CVE-2026-1299
Severity CVSS v4.0:
MEDIUM
Type:
CWE-93
Improper Neutralization of CRLF Sequences ('CRLF Injection')
Publication date:
23/01/2026
Last modified:
23/01/2026
Description
The <br />
email module, specifically the "BytesGenerator" class, didn’t properly quote newlines for email headers when <br />
serializing an email message allowing for header injection when an email<br />
is serialized. This is only applicable if using "LiteralHeader" writing headers that don&#39;t respect email folding rules, the new behavior will reject the incorrectly folded headers in "BytesGenerator".
Impact
Base Score 4.0
6.00
Severity 4.0
MEDIUM
References to Advisories, Solutions, and Tools
- https://cve.org/CVERecord?id=CVE-2024-6923
- https://github.com/python/cpython/commit/052e55e7d44718fe46cbba0ca995cb8fcc359413
- https://github.com/python/cpython/issues/144125
- https://github.com/python/cpython/pull/144126
- https://mail.python.org/archives/list/security-announce@python.org/thread/6ZZULGALJTITEAGEXLDJE2C6FORDXPBT/



