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Fencer Vulns
critical 9.2

CVE-2026-19445 json

Use-after-free of a server-side SSLContext when sni_callback switches contexts

published 2026-09-30 39 d ago modified 2026-10-09 31 d ago also BIT-libpython-2026-19445 , BIT-python-2026-19445 , BIT-python-min-2026-19445 , EUVD-2026-90077

cvss
9.2
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits
0
none known

Summary

A remote, unauthenticated TLS client can make a server crash or call through a freed pointer if its sni_callback assigns a different context to SSLSocket.context (the documented way to select a certificate per server name) and nothing else keeps the original ssl.SSLContext alive. Typical cases are servers that create an SSLContext per connection or replace it while connections are open; servers that wrap their listening socket with it are not affected.

Mitigation: keep a reference to every SSLContext that sets sni_callback for the lifetime of the server. TLS clients are not affected.

Patch / fix

  • bitnami libpython 3.10.22, 3.11.17, 3.12.15, 3.13.16, 3.14.8
  • bitnami python 3.10.22, 3.11.17, 3.12.15, 3.13.16, 3.14.8
  • bitnami python-min 3.10.22, 3.11.17, 3.12.15, 3.13.16, 3.14.8
  • Python Software Foundation CPython 3.10.22, 3.11.17, 3.12.15, 3.13.16, 3.14.8, 3.15.0rc3
  • pypy3 Debian 14 8.0.1+dfsg-1
  • python3.11 Debian 12 3.11.2-6+deb12u9
  • python3.14 Debian 14 3.14.8-1
  • python3.15 Debian 14 3.15.0~rc3-1

debian advisories DEBIAN-CVE-2026-19445

  • python3 RHEL 8 3.6.8-79.el8_10
  • python3-idle RHEL 8 3.6.8-79.el8_10
  • python3-libs RHEL 8 3.6.8-79.el8_10
  • python3-test RHEL 8 3.6.8-79.el8_10
  • platform-python RHEL 8 3.6.8-79.el8_10
  • python3-tkinter RHEL 8 3.6.8-79.el8_10
  • python3.14 RHEL 9 3.14.8-1.el9_8
  • python3.14-idle RHEL 9 3.14.8-1.el9_8

red hat advisories RHSA-2026:85239RHSA-2026:77021RHSA-2026:77020RHSA-2026:77018RHSA-2026:77017RHSA-2026:77028

  • python311 SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Python 3 15 SP7 3.11.17-150600.3.74.1
  • python311-core SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Python 3 15 SP7 +1 more 3.11.17-150600.3.74.1
  • python313 SLE Module for Python 3 15 SP7 3.13.16-150700.4.61.1
  • python313-core SLE Module for Python 3 15 SP7 3.13.16-150700.4.61.1
  • python SLE Module for Package Hub 15 SP7 2.7.18-150000.139.1
  • python-base SLE Module for Package Hub 15 SP7 2.7.18-150000.139.2
  • python311 SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +6 more 3.11.17-150400.9.105.1
  • python311-core SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +6 more 3.11.17-150400.9.105.1

suse advisories SUSE-SU-2026:4946-1SUSE-SU-2026:4941-1SUSE-SU-2026:4919-1SUSE-SU-2026:4809-1SUSE-SU-2026:24280-1SUSE-SU-2026:24325-1

  • python316 openSUSE Tumbleweed 3.16.0~a1-1.1
  • python311 openSUSE Tumbleweed 3.11.17-1.1
  • python312 openSUSE Tumbleweed 3.12.15-1.1
  • python313 openSUSE Tumbleweed 3.13.16-1.1
  • python314 openSUSE Tumbleweed 3.14.8-1.1
  • python310 openSUSE Tumbleweed 3.10.22-1.1
  • python315 openSUSE Tumbleweed 3.15.0~rc3-1.1

opensuse advisories openSUSE-SU-2026:12477-1openSUSE-SU-2026:12121-1openSUSE-SU-2026:12122-1openSUSE-SU-2026:12123-1openSUSE-SU-2026:12124-1openSUSE-SU-2026:12087-1

  • python3 AlmaLinux 9 3.9.25-7.el9_8.6
  • python3-idle AlmaLinux 9 3.9.25-7.el9_8.6
  • python3-libs AlmaLinux 9 3.9.25-7.el9_8.6
  • python3-test AlmaLinux 9 3.9.25-7.el9_8.6
  • python3-tkinter AlmaLinux 9 3.9.25-7.el9_8.6
  • python-unversioned-command AlmaLinux 9 3.9.25-7.el9_8.6
  • python3-idle AlmaLinux 8 3.6.8-79.el8_10.alma.1
  • python3-libs AlmaLinux 8 3.6.8-79.el8_10.alma.1

almalinux advisories ALSA-2026:89742ALSA-2026:85239ALSA-2026:77017ALSA-2026:77018ALSA-2026:77020ALSA-2026:77021

  • python3.9 Rocky Linux 9 3.9.25-7.el9_8.6
  • python3 Rocky Linux 8 3.6.8-79.el8_10.rocky.0
  • python3.14 Rocky Linux 10 3.14.8-1.el10_2
  • python3.12 Rocky Linux 10 3.12.15-1.el10_2
  • python3.12 Rocky Linux 9 3.12.15-1.el9_8
  • python3.14 Rocky Linux 9 3.14.8-1.el9_8
  • python3.12 Rocky Linux 8 3.12.15-2.el8_10

rocky linux advisories RLSA-2026:89742RLSA-2026:85239RLSA-2026:77018RLSA-2026:77020RLSA-2026:77017RLSA-2026:77021

  • python3 Alpine 3.23, Alpine 3.22, Alpine 3.21 3.12.15-r0
  • python3 Alpine 3.24 3.14.8-r0

alpine advisories ALPINE-CVE-2026-19445

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • python3 Azure Linux 3.0 3.12.15-1

azure linux advisories AZL-105690

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-19445 updated cvss 8.1

python: Use-after-free of a server-side SSLContext when sni_callback switches contexts

  • Red Hat Enterprise Linux 7 python3, python3-idle, python3-libs, python3-test, python3-tkinter
    affected: workaround, no fix available
  • Red Hat Enterprise Linux 8 python3.11, python3.11-idle, python3.11-libs, python3.11-test, python3.11-tkinter, python3.11-rpm-macros Red Hat Enterprise Linux 9 python3.11, python3.11-idle, python3.11-libs, python3.11-test, python3.11-tkinter
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-dashboard-rhel9
    under investigation
  • Red Hat Cost Management On-Premise 1 costmanagement/costmanagement-ui-rhel10 1792605272
    fixed: vendor fix RHSA-2026:87400
  • Red Hat Discovery 2 discovery/discovery-ui-rhel9 1793733716, discovery/discovery-server-rhel9 1793734080
    fixed: vendor fix RHSA-2026:94802
  • Red Hat Enterprise Linux AppStream (v. 8) python3.12 3.12.15-2.el8_10, python3-idle 3.6.8-79.el8_10, python3-test 3.6.8-79.el8_10, platform-python 3.6.8-79.el8_10, python3-tkinter 3.6.8-79.el8_10, python3.12-libs 3.12.15-2.el8_10, +2 more
    fixed: vendor fix RHSA-2026:85239
  • Red Hat Enterprise Linux AppStream (v. 9) python3.14 3.14.8-1.el9_8, python3.12 3.12.15-1.el9_8, python3.14-libs 3.14.8-1.el9_8, python3.12-libs 3.12.15-1.el9_8, python3-tkinter 3.9.25-7.el9_8.6, python3.14-tkinter 3.14.8-1.el9_8, +2 more
    fixed: vendor fix RHSA-2026:89742
  • Red Hat Enterprise Linux AppStream (v. 10) python3.14 3.14.8-1.el10_2, python3.14-libs 3.14.8-1.el10_2, python3-tkinter 3.12.15-1.el10_2, python3.14-tkinter 3.14.8-1.el10_2, python-unversioned-command 3.12.15-1.el10_2
    fixed: vendor fix RHSA-2026:77020
show 17 more
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) python3-idle 3.6.8-39.el8_4.13, python3-test 3.6.8-39.el8_4.13, platform-python 3.6.8-39.el8_4.13, python3-tkinter 3.6.8-39.el8_4.13
    fixed: vendor fix RHSA-2026:95082
  • Red Hat Enterprise Linux AppStream AUS (v.8.6) python3-idle 3.6.8-47.el8_6.16, python3-test 3.6.8-47.el8_6.16, platform-python 3.6.8-47.el8_6.16, python3-tkinter 3.6.8-47.el8_6.16
    fixed: vendor fix RHSA-2026:94443
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) python3-idle 3.6.8-39.el8_4.13, python3-test 3.6.8-39.el8_4.13, platform-python 3.6.8-39.el8_4.13, python3-tkinter 3.6.8-39.el8_4.13
    fixed: vendor fix RHSA-2026:95082
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) python3-idle 3.6.8-47.el8_6.16, python3-test 3.6.8-47.el8_6.16, platform-python 3.6.8-47.el8_6.16, python3-tkinter 3.6.8-47.el8_6.16
    fixed: vendor fix RHSA-2026:94443
  • Red Hat Enterprise Linux BaseOS (v. 8) python3 3.6.8-79.el8_10, python3-libs 3.6.8-79.el8_10, python3-test 3.6.8-79.el8_10, platform-python 3.6.8-79.el8_10
    fixed: vendor fix RHSA-2026:85239
  • Red Hat Enterprise Linux BaseOS (v. 9) python3 3.9.25-7.el9_8.6, python3.9 3.9.25-7.el9_8.6, python3-libs 3.9.25-7.el9_8.6
    fixed: vendor fix RHSA-2026:89742
  • Red Hat Enterprise Linux BaseOS (v. 10) python3 3.12.15-1.el10_2, python3.12 3.12.15-1.el10_2, python3-libs 3.12.15-1.el10_2
    fixed: vendor fix RHSA-2026:77020
  • Red Hat Enterprise Linux BaseOS AUS (v.8.4) python3 3.6.8-39.el8_4.13, python3-libs 3.6.8-39.el8_4.13, python3-test 3.6.8-39.el8_4.13, platform-python 3.6.8-39.el8_4.13
    fixed: vendor fix RHSA-2026:95082
  • Red Hat Enterprise Linux BaseOS AUS (v.8.6) python3 3.6.8-47.el8_6.16, python3-libs 3.6.8-47.el8_6.16, python3-test 3.6.8-47.el8_6.16, platform-python 3.6.8-47.el8_6.16
    fixed: vendor fix RHSA-2026:94443
  • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4) python3 3.6.8-39.el8_4.13, python3-libs 3.6.8-39.el8_4.13, python3-test 3.6.8-39.el8_4.13, platform-python 3.6.8-39.el8_4.13
    fixed: vendor fix RHSA-2026:95082
  • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) python3 3.6.8-47.el8_6.16, python3-libs 3.6.8-47.el8_6.16, python3-test 3.6.8-47.el8_6.16, platform-python 3.6.8-47.el8_6.16
    fixed: vendor fix RHSA-2026:94443
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) python3 3.9.25-7.el9_8.6, python3.14 3.14.8-1.el9_8, python3.12 3.12.15-1.el9_8, python3-idle 3.9.25-7.el9_8.6, python3-test 3.9.25-7.el9_8.6, python3.14-idle 3.14.8-1.el9_8, +11 more
    fixed: vendor fix RHSA-2026:89742
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) python3-idle 3.12.15-1.el10_2, python3-test 3.12.15-1.el10_2, python3.14-idle 3.14.8-1.el10_2, python3.14-test 3.14.8-1.el10_2, python3.14-freethreading 3.14.8-1.el10_2, python3.14-freethreading-idle 3.14.8-1.el10_2, +3 more
    fixed: vendor fix RHSA-2026:77020
  • Red Hat Enterprise Linux CRB (v. 8) python3.12 3.12.15-2.el8_10, python3.12-idle 3.12.15-2.el8_10, python3.12-test 3.12.15-2.el8_10, python3.12-tkinter 3.12.15-2.el8_10
    fixed: vendor fix RHSA-2026:77028
  • Red Hat Hardened Images python3.15 3.15.0~rc2-1.1.hum1, python3.15-idle 3.15.0~rc2-1.1.hum1, python3.15-libs 3.15.0~rc2-1.1.hum1, python3.15-test 3.15.0~rc2-1.1.hum1, python3.15-tkinter 3.15.0~rc2-1.1.hum1, python3.15-freethreading 3.15.0~rc2-1.1.hum1, +4 more
    fixed: vendor fix RHSA-2026:74867
  • Red Hat Update Infrastructure 5 rhui5/cds-rhel9 1791978528, rhui5/rhua-rhel9 1791978693, rhui5/installer-rhel9 1791964013, rhui5/cds-kubernetes-rhel9 1791978534
    fixed: vendor fix RHSA-2026:82939
  • Red Hat Enterprise Linux 6 python, tkinter, python-libs, python-test, python-tools Red Hat Enterprise Linux 7 python, tkinter, python-libs, python-test, python-tools Red Hat Enterprise Linux 8 scipy, python36, python-nose, python-wheel, python3-bson, python3-nose, +19 more Red Hat Hardened Images hi/python, python3.11, python3.14 3.14.8-1.hum1, python3.10 3.10.22-1.hum1, python3.12 3.12.15-1.hum1, python3.13 3.13.16-1.hum1 Red Hat Update Infrastructure 5 rhui5/haproxy-rhel9 1791978528
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.52% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 9.2 CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N
CNA 4.0 9.2 CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/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

Affected packages

ecosystem package affected fixed in
bitnami libpython
<3.10.22
>=3.11.0, <3.11.17
>=3.12.0, <3.12.15
>=3.13.0, <3.13.16
>=3.14.0, <3.14.8
3.10.22
3.11.17
3.12.15
3.13.16
3.14.8
bitnami python
<3.10.22
>=3.11.0, <3.11.17
>=3.12.0, <3.12.15
>=3.13.0, <3.13.16
>=3.14.0, <3.14.8
3.10.22
3.11.17
3.12.15
3.13.16
3.14.8
bitnami python-min
<3.10.22
>=3.11.0, <3.11.17
>=3.12.0, <3.12.15
>=3.13.0, <3.13.16
>=3.14.0, <3.14.8
3.10.22
3.11.17
3.12.15
3.13.16
3.14.8

Affected products

  • Python Software Foundation CPython

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.