Bug 2432437 (CVE-2026-1299)

Summary:	CVE-2026-1299 cpython: email header injection due to unquoted newlines
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	bbrownin, dfreiber, drow, gotiwari, jburrell, jgrulich, jhorak, jkoehler, ljawale, lphiri, luizcosta, mvyas, nweather, rbobbitt, sdawley, teagle, tpopela, vkumar
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the email module in the Python standard library. When serializing an email message, the BytesGenerator class fails to properly quote newline characters for email headers. This issue is exploitable when the LiteralHeader class is used as it does not respect email folding rules, allowing an attacker to inject email headers and potentially modify message recipients or the email body, and spoof sender information.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2433810, 2433813, 2433823, 2433811, 2433812, 2433814, 2433815, 2433816, 2433817, 2433818, 2433819, 2433820, 2433821, 2433822, 2433824, 2433825, 2433826, 2433827, 2433828, 2433829, 2433830, 2433831, 2433832
Bug Blocks:

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

Comment 4 errata-xmlrpc 2026-03-10 09:27:05 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:4165 https://access.redhat.com/errata/RHSA-2026:4165

Comment 5 errata-xmlrpc 2026-03-10 09:51:32 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:4168 https://access.redhat.com/errata/RHSA-2026:4168

Comment 7 errata-xmlrpc 2026-03-10 22:28:26 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:4216 https://access.redhat.com/errata/RHSA-2026:4216

Comment 9 errata-xmlrpc 2026-03-12 12:28:04 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:4463 https://access.redhat.com/errata/RHSA-2026:4463

Comment 10 errata-xmlrpc 2026-03-12 13:30:28 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:4473 https://access.redhat.com/errata/RHSA-2026:4473

Comment 11 errata-xmlrpc 2026-03-17 10:33:34 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:4713 https://access.redhat.com/errata/RHSA-2026:4713

Comment 12 errata-xmlrpc 2026-03-17 11:04:31 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.6 Extended Update Support

Via RHSA-2026:4746 https://access.redhat.com/errata/RHSA-2026:4746

Comment 14 errata-xmlrpc 2026-03-19 17:53:35 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
  Red Hat Enterprise Linux 8.8 Telecommunications Update Service

Via RHSA-2026:5152 https://access.redhat.com/errata/RHSA-2026:5152

Comment 15 errata-xmlrpc 2026-03-23 01:30:32 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.2 Advanced Update Support

Via RHSA-2026:5216 https://access.redhat.com/errata/RHSA-2026:5216

Comment 16 errata-xmlrpc 2026-03-23 01:38:35 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On

Via RHSA-2026:5221 https://access.redhat.com/errata/RHSA-2026:5221

Comment 17 errata-xmlrpc 2026-03-23 02:13:48 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Via RHSA-2026:5223 https://access.redhat.com/errata/RHSA-2026:5223

Comment 18 errata-xmlrpc 2026-03-23 02:14:15 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions

Via RHSA-2026:5219 https://access.redhat.com/errata/RHSA-2026:5219

Comment 19 errata-xmlrpc 2026-03-23 02:29:54 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions
  Red Hat Enterprise Linux 8.6 Telecommunications Update Service

Via RHSA-2026:5215 https://access.redhat.com/errata/RHSA-2026:5215

Comment 20 errata-xmlrpc 2026-03-23 02:33:15 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.6 Extended Update Support

Via RHSA-2026:5218 https://access.redhat.com/errata/RHSA-2026:5218

Comment 21 errata-xmlrpc 2026-03-23 02:36:51 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.6 Extended Update Support

Via RHSA-2026:5220 https://access.redhat.com/errata/RHSA-2026:5220

Comment 22 errata-xmlrpc 2026-03-23 03:23:38 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Via RHSA-2026:5225 https://access.redhat.com/errata/RHSA-2026:5225

Comment 23 errata-xmlrpc 2026-03-23 03:46:04 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.4 Extended Update Support

Via RHSA-2026:5226 https://access.redhat.com/errata/RHSA-2026:5226

Comment 24 errata-xmlrpc 2026-03-23 05:20:25 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10.0 Extended Update Support

Via RHSA-2026:5315 https://access.redhat.com/errata/RHSA-2026:5315

Comment 25 errata-xmlrpc 2026-03-23 15:57:43 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.4 Extended Update Support

Via RHSA-2026:5399 https://access.redhat.com/errata/RHSA-2026:5399

Comment 26 errata-xmlrpc 2026-03-30 01:42:39 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
  Red Hat Enterprise Linux 8.8 Telecommunications Update Service

Via RHSA-2026:6008 https://access.redhat.com/errata/RHSA-2026:6008

Comment 27 errata-xmlrpc 2026-03-31 09:03:16 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.4 Extended Update Support

Via RHSA-2026:6253 https://access.redhat.com/errata/RHSA-2026:6253

Comment 28 errata-xmlrpc 2026-04-02 12:01:07 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7 Extended Lifecycle Support

Via RHSA-2026:6464 https://access.redhat.com/errata/RHSA-2026:6464