CRLF injection in Python - CVE-2026-1299

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Main Vulnerability Database Vulnerabilities #VU122817

CRLF injection in Python - CVE-2026-1299

Published: February 13, 2026


Vulnerability identifier: #VU122817
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N]
CVE-ID: CVE-2026-1299
CWE-ID: CWE-93
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to inject arbitrary header into email messages.

The vulnerability exists due to insufficient validation of attacker-supplied data in "BytesGenerator" class. A remote attacker can pass specially crafted data to the application containing CR-LF characters and perform a spoofing attack.


Affected software

Python
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 12 SP5 LTSS Extended
SUSE Linux Enterprise Server 12 SP5
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server for SAP Applications 12
SUSE Linux Enterprise High Performance Computing 12
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Real Time 15
SUSE Linux Enterprise Micro
SUSE Linux Enterprise Micro for Rancher
Red Hat Enterprise Linux for Power, little endian
Red Hat CodeReady Linux Builder for IBM z Systems
Anolis OS
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for ARM 64
Red Hat CodeReady Linux Builder for ARM 64
Red Hat CodeReady Linux Builder for Power, little endian
Red Hat CodeReady Linux Builder for x86_64
Red Hat Enterprise Linux Server - AUS
Red Hat Enterprise Linux Server - TUS
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat CodeReady Linux Builder for Power, little endian - Extended Update Support
Red Hat CodeReady Linux Builder for ARM 64 - Extended Update Support
Red Hat CodeReady Linux Builder for IBM z Systems - Extended Update Support
Red Hat CodeReady Linux Builder for x86_64 - Extended Update Support
SUSE Package Hub 15
Development Tools Module
Basesystem Module
openSUSE Leap
openEuler
Fedora
IBM Watson Speech Services Cartridge for IBM Cloud Pak for Data
Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
python-base-debugsource
python-base-debuginfo
python-debuginfo
python-demo
python-gdbm
libpython2_7-1_0-debuginfo-32bit
libpython2_7-1_0-32bit
python-debuginfo-32bit
python-base-debuginfo-32bit
python-base-32bit
python-32bit
python-doc-pdf
python-doc
python-curses
python-xml-debuginfo
python-gdbm-debuginfo
python-tk-debuginfo
python-tk
python-curses-debuginfo
python-base
python-debugsource
python-devel
python-xml
libpython2_7-1_0
python
python-idle
libpython2_7-1_0-debuginfo
python-32bit-debuginfo
python-base-32bit-debuginfo
libpython2_7-1_0-32bit-debuginfo
python3-tk
libpython3_4m1_0-debuginfo-32bit
libpython3_4m1_0
python3-base-debuginfo-32bit
libpython3_4m1_0-32bit
python3-devel-debuginfo
python3-tk-debuginfo
python3-debugsource
python3-curses-debuginfo
python3-base
python3
python3-base-debuginfo
python3-curses
python3-devel
python3-debuginfo
python3-base-debugsource
libpython3_4m1_0-debuginfo
python3 (Red Hat package)
python3-tkinter
platform-python
platform-python-debug
platform-python-devel
python3-idle
python3-libs
python3-test
python3.6
python36-debugsource
python36-base
libpython3_6m1_0-debuginfo
libpython3_6m1_0
python36
python36-base-debuginfo
python36-debuginfo
python36-devel
libpython3_6m1_0-debuginfo-32bit
libpython3_6m1_0-32bit
python3-tools
python3-dbm
python3-doc
python3-testsuite-debuginfo
python3-doc-devhelp
python3-dbm-debuginfo
libpython3_6m1_0-32bit-debuginfo
libpython3_6m1_0-64bit
python3-testsuite
libpython3_6m1_0-64bit-debuginfo
python3-core-debugsource
python3-debug
python3-unversioned-command
python3-help
python3.9 (Red Hat package)
python3.9
python3.10
python3.11 (Red Hat package)
python-unversioned-command
python3.11-test
python3.11-debug
python3.11-libs
python3.11-tkinter
python3.11-rpm-macros
python3.11-idle
python3.11-devel
python3.11
mingw-python3
python3.12 (Red Hat package)
python3.12
python3.14
python3-docs

How to mitigate CVE-2026-1299

Install updates from vendor's website.

Python - addressed in versions 3.13.12, 3.14.3, 3.15.0a6
IBM Watson Speech Services Cartridge for IBM Cloud Pak for Data - update to 5.3.1 Patch 2
python-base-debugsource - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
python-base-debuginfo - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
python-debuginfo - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
python-demo - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
python-gdbm - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
libpython2_7-1_0-debuginfo-32bit - update to 2.7.18-33.69.1
libpython2_7-1_0-32bit - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
python-debuginfo-32bit - update to 2.7.18-33.69.1
python-base-debuginfo-32bit - update to 2.7.18-33.69.1
python-base-32bit - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
python-32bit - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
python-doc-pdf - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
python-doc - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
python-curses - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
python-xml-debuginfo - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
python-gdbm-debuginfo - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
python-tk-debuginfo - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
python-tk - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
python-curses-debuginfo - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
python-base - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
python-debugsource - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
python-devel - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
python-xml - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
libpython2_7-1_0 - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
python - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
python-idle - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
libpython2_7-1_0-debuginfo - addressed in versions 2.7.18-33.69.1, 2.7.18-150000.108.1
python-32bit-debuginfo - update to 2.7.18-150000.108.1
python-base-32bit-debuginfo - update to 2.7.18-150000.108.1
libpython2_7-1_0-32bit-debuginfo - update to 2.7.18-150000.108.1
python3-tk - addressed in versions 3.4.10-25.175.1, 3.6.15-150300.10.109.1
libpython3_4m1_0-debuginfo-32bit - update to 3.4.10-25.175.1
libpython3_4m1_0 - update to 3.4.10-25.175.1
python3-base-debuginfo-32bit - update to 3.4.10-25.175.1
libpython3_4m1_0-32bit - update to 3.4.10-25.175.1
python3-devel-debuginfo - addressed in versions 3.4.10-25.175.1, 3.6.15-150300.10.109.1
python3-tk-debuginfo - addressed in versions 3.4.10-25.175.1, 3.6.15-150300.10.109.1
python3-debugsource - addressed in versions 3.4.10-25.175.1, 3.6.15-150300.10.109.1
python3-curses-debuginfo - addressed in versions 3.4.10-25.175.1, 3.6.15-150300.10.109.1
python3-base - addressed in versions 3.4.10-25.175.1, 3.6.15-150300.10.109.1
python3 - addressed in versions 3.4.10-25.175.1, 3.6.15-150300.10.109.1
python3-base-debuginfo - addressed in versions 3.4.10-25.175.1, 3.6.15-150300.10.109.1
python3-curses - addressed in versions 3.4.10-25.175.1, 3.6.15-150300.10.109.1
python3-devel - addressed in versions 3.4.10-25.175.1, 3.6.15-150300.10.109.1
python3-debuginfo - addressed in versions 3.4.10-25.175.1, 3.6.15-150300.10.109.1
python3-base-debugsource - update to 3.4.10-25.175.1
libpython3_4m1_0-debuginfo - update to 3.4.10-25.175.1
python3 (Red Hat package) - addressed in versions 3.6.8-21.el7_9.4, 3.6.8-24.el8_2.6, 3.6.8-39.el8_4.9, 3.6.8-47.el8_6.11, 3.6.8-51.el8_8.13, 3.6.8-73.el8_10
python3-tkinter - addressed in versions 3.6.8-73.0.1, 3.11.6-16
platform-python - update to 3.6.8-73.0.1
platform-python-debug - update to 3.6.8-73.0.1
platform-python-devel - update to 3.6.8-73.0.1
python3-devel - addressed in versions 3.6.8-73.0.1, 3.11.6-16
python3-idle - addressed in versions 3.6.8-73.0.1, 3.11.6-16
python3-libs - addressed in versions 3.6.8-73.0.1, 3.11.6-16
python3-test - addressed in versions 3.6.8-73.0.1, 3.11.6-16
python3.6 - addressed in versions 3.6.15-52.fc42, 3.6.15-52.fc43
python36-debugsource - update to 3.6.15-103.1
python36-base - update to 3.6.15-103.1
libpython3_6m1_0-debuginfo - addressed in versions 3.6.15-103.1, 3.6.15-150300.10.109.1
libpython3_6m1_0 - addressed in versions 3.6.15-103.1, 3.6.15-150300.10.109.1
python36 - update to 3.6.15-103.1
python36-base-debuginfo - update to 3.6.15-103.1
python36-debuginfo - update to 3.6.15-103.1
python36-devel - update to 3.6.15-103.1
libpython3_6m1_0-debuginfo-32bit - update to 3.6.15-103.1
libpython3_6m1_0-32bit - addressed in versions 3.6.15-103.1, 3.6.15-150300.10.109.1
python3-tools - update to 3.6.15-150300.10.109.1
python3-dbm - update to 3.6.15-150300.10.109.1
python3-doc - update to 3.6.15-150300.10.109.1
python3-testsuite-debuginfo - update to 3.6.15-150300.10.109.1
python3-doc-devhelp - update to 3.6.15-150300.10.109.1
python3-dbm-debuginfo - update to 3.6.15-150300.10.109.1
libpython3_6m1_0-32bit-debuginfo - update to 3.6.15-150300.10.109.1
libpython3_6m1_0-64bit - update to 3.6.15-150300.10.109.1
python3-idle - update to 3.6.15-150300.10.109.1
python3-testsuite - update to 3.6.15-150300.10.109.1
libpython3_6m1_0-64bit-debuginfo - update to 3.6.15-150300.10.109.1
python3-core-debugsource - update to 3.6.15-150300.10.109.1
python3-debug - addressed in versions 3.9.9-52, 3.11.6-20, 3.11.6-23, 3.11.6-24
python3 - addressed in versions 3.9.9-52, 3.11.6-20, 3.11.6-23, 3.11.6-24
python3-debuginfo - addressed in versions 3.9.9-52, 3.11.6-20, 3.11.6-23, 3.11.6-24
python3-debugsource - addressed in versions 3.9.9-52, 3.11.6-20, 3.11.6-23, 3.11.6-24
python3-devel - addressed in versions 3.9.9-52, 3.11.6-20, 3.11.6-23, 3.11.6-24
python3-unversioned-command - addressed in versions 3.9.9-52, 3.11.6-20, 3.11.6-23, 3.11.6-24
python3-help - addressed in versions 3.9.9-52, 3.11.6-20, 3.11.6-23, 3.11.6-24
python3.9 (Red Hat package) - update to 3.9.25-3.el9_7.1
python3.9 - addressed in versions 3.9.25-6.fc42, 3.9.25-6.fc43
python3.10 - addressed in versions 3.10.19-4.fc42, 3.10.19-4.fc43, 3.10.19-4.fc44
python3.11 (Red Hat package) - addressed in versions 3.11.2-2.el8_8.8, 3.11.7-1.el9_4.11, 3.11.13-5.1.el9_7
python-unversioned-command - update to 3.11.6-16
python3-debug - update to 3.11.6-16
python3 - update to 3.11.6-16
python3-tkinter - addressed in versions 3.11.6-20, 3.11.6-23, 3.11.6-24
python3.11-test - update to 3.11.13-5.0.1
python3.11-debug - update to 3.11.13-5.0.1
python3.11-libs - update to 3.11.13-5.0.1
python3.11-tkinter - update to 3.11.13-5.0.1
python3.11-rpm-macros - update to 3.11.13-5.0.1
python3.11-idle - update to 3.11.13-5.0.1
python3.11-devel - update to 3.11.13-5.0.1
python3.11 - update to 3.11.13-5.0.1
python3.11 - addressed in versions 3.11.14-5.fc42, 3.11.14-5.fc43, 3.11.14-5.fc44
mingw-python3 - addressed in versions 3.11.14-7.fc42, 3.11.14-7.fc43
python3.12 (Red Hat package) - addressed in versions 3.12.1-4.el9_4.11, 3.12.9-1.el9_6.6, 3.12.9-2.el10_0.7, 3.12.12-3.el8_10, 3.12.12-4.el9_7.1
python3.12 - addressed in versions 3.12.12-4.fc42, 3.12.12-4.fc43, 3.12.12-4.fc44, 3.12.13-1.fc42, 3.12.13-1.fc44
python3.14 - addressed in versions 3.14.3-1.fc42, 3.14.3-1.fc43
python3-docs - update to 3.14.3-1.fc43

External References

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