Name: CVE-2026-1299: Improper Neutralization of CRLF Sequences
Creator: Rapid7
Published: 2026-01-23T00:00:00.000Z
License: https://www.rapid7.com/legal/website-terms-of-use/
Keywords: CVE, CVE-2026-1299, CVSS 6, EPSS 0.00582

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".

CVSS Details

CVSS 4.0 Base Score: 6 (MEDIUM)
CVSS 4.0 Vector: (CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X)

Covered by Rapid7

Product	Vendor Advisory	Solution File	Added	Published
Alma_linux	—	Upgrade python3-develUpgrade platform-python-debugUpgrade python3.12-rpm-macrosUpgrade python3.12-testUpgrade python3-libsUpgrade python-unversioned-commandUpgrade platform-python-develUpgrade python3.11-develUpgrade python3.11-debugUpgrade python3-idleUpgrade python3-tkinterUpgrade python3.12-develUpgrade python3.11-idleUpgrade python3.11-libsUpgrade python3.12-tkinterUpgrade platform-pythonUpgrade python3.12-idleUpgrade python3.11-tkinterUpgrade python3-testUpgrade python3Upgrade python3.11-testUpgrade python3.11-rpm-macrosUpgrade python3.12Upgrade python3-debugUpgrade python3.11Upgrade python3.12-debugUpgrade python3.12-libs	Feb 9, 2026	Feb 5, 2026
Amazon Linux Ami 2	—	Upgrade python3-tkinterUpgrade python3-develUpgrade python3-toolsUpgrade python3Upgrade python3-debugUpgrade python3-testUpgrade python3-libsUpgrade python3-debuginfo	May 20, 2026	May 20, 2026
Amazon_linux_2023	—	Upgrade python3.13-freethreadingUpgrade python3-develUpgrade python3.12-develUpgrade python3.13-debugUpgrade python3.11-debuginfoUpgrade python3.12-idleUpgrade python3.11-libsUpgrade python-unversioned-commandUpgrade python3-idleUpgrade python3.13-idleUpgrade python3-libsUpgrade python3.13-develUpgrade python3.12-testUpgrade python3.11-idleUpgrade python3.13-freethreading-debugUpgrade python3.13-testUpgrade python3.13-debugsourceUpgrade python3.13-tkinterUpgrade python3.9-debuginfoUpgrade python3.13Upgrade python3.12Upgrade python3.11Upgrade python3.13-libsUpgrade python3.12-libsUpgrade python3.13-debuginfoUpgrade python3-tkinterUpgrade python3.11-testUpgrade python3.12-debugUpgrade python3.11-debugsourceUpgrade python3.11-tkinterUpgrade python3.11-debugUpgrade python3-testUpgrade python3.12-debugsourceUpgrade python3.12-debuginfoUpgrade python3Upgrade python3.12-tkinterUpgrade python3.11-develUpgrade python3-debugUpgrade python3.9-debugsource	Feb 20, 2026	Jan 23, 2026
Debian	—	Upgrade python3.11Upgrade python3.9Upgrade python3.13	Jan 27, 2026	Jan 27, 2026
Freebsd	—	Upgrade python311Upgrade python312Upgrade python310Upgrade python314Upgrade python313tUpgrade python313	Feb 12, 2026	Feb 4, 2026
Nutanix Ahv	—	Upgrade Nutanix AHV to the latest version	Jun 5, 2026	Jun 2, 2026
Oracle_linux	—	Upgrade python3.12Upgrade python3.11-rpm-macrosUpgrade python3-tkinterUpgrade python3.11-idleUpgrade python3-libsUpgrade python3-debugUpgrade python3-develUpgrade python3.11-develUpgrade python3.12-tkinterUpgrade python3.11-debugUpgrade python3-testUpgrade python3.11Upgrade python3.11-testUpgrade platform-python-debugUpgrade python3.12-debugUpgrade python3.12-idleUpgrade python3Upgrade platform-pythonUpgrade python3.11-libsUpgrade python3-idleUpgrade python-unversioned-commandUpgrade python3.12-develUpgrade python3.12-libsUpgrade python3.11-tkinterUpgrade python3.12-rpm-macrosUpgrade python3.12-testUpgrade platform-python-devel	Feb 9, 2026	Jan 23, 2026
Redhat_linux	—	No solution existsUpgrade python3.11-idleUpgrade python3.12-debuginfoUpgrade python3.11-develUpgrade python3-testUpgrade python3.11-debuginfoUpgrade python3.12Upgrade python3-tkinterUpgrade python3.12-tkinterUpgrade python3-debugsourceUpgrade python3.11-debugsourceUpgrade python3.11-rpm-macrosUpgrade python3-debugUpgrade python3.9-debuginfoUpgrade python3.12-idleUpgrade python3.12-develUpgrade platform-pythonUpgrade python3.11-libsUpgrade python3Upgrade python3.12-debugsourceUpgrade python3.11-testUpgrade python3-idleUpgrade python3.12-rpm-macrosUpgrade python3.12-debugUpgrade python3.11Upgrade python3.11-tkinterUpgrade python3.12-testUpgrade platform-python-debugUpgrade python3.11-debugUpgrade python3-libsUpgrade python3.9-debugsourceUpgrade platform-python-develUpgrade python-unversioned-commandUpgrade python3.12-libsUpgrade python3-develUpgrade python3-debuginfo	Mar 13, 2026	Jan 23, 2026
Rocky_linux	—	Upgrade python3.11Upgrade python3.9-debugsourceUpgrade python3.9-debuginfoUpgrade python3-tkinterUpgrade python3.11-develUpgrade python3-develUpgrade python3.12-develUpgrade python3-libsUpgrade python3.11-debugsourceUpgrade python3.12-tkinterUpgrade python3-idleUpgrade python3.11-testUpgrade python3.12-libsUpgrade python3Upgrade python3.12-debugUpgrade python3.11-debugUpgrade python3.11-tkinterUpgrade python3.12-debugsourceUpgrade python3.11-libsUpgrade python3-debugUpgrade python3.12Upgrade python3.11-debuginfoUpgrade python3.12-debuginfoUpgrade python3-testUpgrade platform-python-debugUpgrade platform-pythonUpgrade platform-python-develUpgrade python3.12-idleUpgrade python3.12-testUpgrade python3.11-idle	Mar 12, 2026	Mar 11, 2026
Suse	—	Upgrade libpython3_6m1_0Upgrade python-tkUpgrade libpython3_14-1_0Upgrade python310-idleUpgrade python314-idleUpgrade python-baseUpgrade python313-idleUpgrade libpython3_13-1_0Upgrade python3-doc-devhelpUpgrade python312-32bitUpgrade python312-base-32bitUpgrade python310-cursesUpgrade python311-baseUpgrade python312-doc-devhelpUpgrade python314-doc-devhelpUpgrade python310-dbmUpgrade python311-testsuiteUpgrade python-docUpgrade python36Upgrade python313-docUpgrade libpython3_6m1_0-32bitUpgrade python313-nogil-dbmUpgrade python313-nogil-idleUpgrade pythonUpgrade python311-32bitUpgrade python310-baseUpgrade libpython3_13t1_0Upgrade python311-tkUpgrade libpython3_11-1_0Upgrade python3-cursesUpgrade python311-idleUpgrade python-doc-pdfUpgrade python310-base-32bitUpgrade python314-cursesUpgrade python310-develUpgrade python312-docUpgrade python313-cursesUpgrade python314-dbmUpgrade python313-dbmUpgrade python310-32bitUpgrade python311-cursesUpgrade libpython3_12-1_0-32bitUpgrade libpython3_4m1_0-32bitUpgrade python310-doc-devhelpUpgrade python-cursesUpgrade python313-nogil-tkUpgrade python313-x86-64-v3Upgrade python314-baseUpgrade python-idleUpgrade python313-toolsUpgrade python314Upgrade libpython3_10-1_0Upgrade libpython3_10-1_0-32bitUpgrade python3-dbmUpgrade python314-develUpgrade libpython3_14-1_0-x86-64-v3Upgrade python36-develUpgrade python314-docUpgrade python313-develUpgrade python311-docUpgrade python311-base-32bitUpgrade python3-develUpgrade libpython3_11-1_0-32bitUpgrade libpython2_7-1_0-32bitUpgrade python36-baseUpgrade python313-nogil-baseUpgrade python313-nogilUpgrade python313-doc-devhelpUpgrade python312Upgrade python3-testsuiteUpgrade python-32bitUpgrade libpython3_4m1_0Upgrade python313-nogil-toolsUpgrade python311-doc-devhelpUpgrade python3-baseUpgrade python3Upgrade python310Upgrade python3-tkUpgrade libpython3_13-1_0-x86-64-v3Upgrade python313-nogil-cursesUpgrade python313-baseUpgrade python313-nogil-testsuiteUpgrade python312-tkUpgrade python-xmlUpgrade python312-testsuiteUpgrade python312-idleUpgrade python310-tkUpgrade python313-tkUpgrade python312-develUpgrade python312-toolsUpgrade python312-cursesUpgrade python311-develUpgrade python310-toolsUpgrade python-demoUpgrade libpython2_7-1_0Upgrade python314-base-x86-64-v3Upgrade python313-testsuiteUpgrade python312-dbmUpgrade python310-docUpgrade python-develUpgrade python314-tkUpgrade python314-toolsUpgrade python3-toolsUpgrade python-base-32bitUpgrade python313-base-x86-64-v3Upgrade python312-baseUpgrade python311-toolsUpgrade python311-dbmUpgrade python311Upgrade libpython3_12-1_0Upgrade python-gdbmUpgrade python313-nogil-develUpgrade python314-x86-64-v3Upgrade python313Upgrade python310-testsuiteUpgrade python3-idleUpgrade python3-doc	Feb 23, 2026	Feb 7, 2026
Ubuntu	—	Upgrade python3.12Upgrade libpython3.12t64Upgrade python3.10Upgrade python3.14Upgrade libpython3.14Upgrade libpython3.10	May 25, 2026	Jan 23, 2026

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CVSS Details

Covered by Rapid7

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