Bug 2432437 (CVE-2026-1299) - CVE-2026-1299 cpython: email header injection due to unquoted newlines
Summary: CVE-2026-1299 cpython: email header injection due to unquoted newlines
Keywords:
Status: NEW
Alias: CVE-2026-1299
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On: 2433810 2433813 2433815 2433816 2433817 2433818 2433820 2433822 2433823 2433825 2433826 2433827 2433828 2433829 2433830 2433832 2433811 2433812 2433814 2433819 2433821 2433824 2433831
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-01-23 17:03 UTC by OSIDB Bzimport
Modified: 2026-02-12 15:34 UTC (History)
18 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHBA-2026:2239 0 None None None 2026-02-09 02:10:36 UTC
Red Hat Product Errata RHBA-2026:2377 0 None None None 2026-02-09 23:44:52 UTC
Red Hat Product Errata RHBA-2026:2666 0 None None None 2026-02-12 15:34:17 UTC
Red Hat Product Errata RHBA-2026:2668 0 None None None 2026-02-12 15:27:13 UTC
Red Hat Product Errata RHSA-2026:2128 0 None None None 2026-02-05 15:34:36 UTC

Description OSIDB Bzimport 2026-01-23 17:03:23 UTC 
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".
Comment 2 errata-xmlrpc 2026-02-05 15:34:34 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:2128 https://access.redhat.com/errata/RHSA-2026:2128
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