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Fencer Vulns
high 7.5

CVE-2025-13836 json

Excessive read buffering DoS in http.client

published 2025-12-01 11 mo ago modified 2026-09-10 59 d ago also BIT-libpython-2025-13836 , BIT-python-2025-13836 , BIT-python-min-2025-13836 , EUVD-2025-200070

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.7%
EPSS 1.7% chance of exploitation in 30 days, percentile 77%
public exploits
0
none known

Summary

When reading an HTTP response from a server, if no read amount is specified, the default behavior will be to use Content-Length. This allows a malicious server to cause the client to read large amounts of data into memory, potentially causing OOM or other DoS.

Patch / fix

  • bitnami libpython 3.10.20, 3.11.15, 3.12.13, 3.13.11, 3.14.1
  • bitnami python 3.10.20, 3.11.15, 3.12.13, 3.13.11, 3.14.1
  • bitnami python-min 3.10.20, 3.11.15, 3.12.13, 3.13.11, 3.14.1
  • Python Software Foundation CPython 3.10.20, 3.11.15, 3.12.13, 3.13.11, 3.14.1, 3.15.0a3
  • pypy3 Debian 14 7.3.21+dfsg-1
  • python3.11 Debian 12 3.11.2-6+deb12u7
  • python3.13 Debian 13 3.13.5-2+deb13u1
  • python3.14 Debian 14 3.14.2-1

debian advisories DEBIAN-CVE-2025-13836

  • python3.10 Ubuntu 22.04 LTS 3.10.12-1~22.04.13
  • python3.12 Ubuntu 24.04 LTS 3.12.3-1ubuntu0.10
  • python3.13 Ubuntu 25.10 3.13.7-1ubuntu0.2
  • python3.14 Ubuntu 25.10 3.14.0-1ubuntu0.1
  • python3.8 Ubuntu Pro 18.04 LTS 3.8.0-3ubuntu1~18.04.2+esm8
  • python3.8 Ubuntu Pro 20.04 LTS 3.8.10-0ubuntu1~20.04.18+esm4
  • python3.9 Ubuntu Pro 20.04 LTS 3.9.5-3ubuntu0~20.04.1+esm8
  • python3.11 Ubuntu Pro 22.04 LTS 3.11.0~rc1-1~22.04.1~esm7

ubuntu advisories UBUNTU-CVE-2025-13836

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • python3.11 hummingbird 1 3.11.15-4.hum1
  • python3.11-idle hummingbird 1 3.11.15-4.hum1
  • python3.11-libs hummingbird 1 3.11.15-4.hum1
  • python3.11-test hummingbird 1 3.11.15-4.hum1
  • python3.11-tkinter hummingbird 1 3.11.15-4.hum1
  • python3.12 hummingbird 1 3.12.13-3.hum1
  • python3.12-idle hummingbird 1 3.12.13-3.hum1
  • python3.12-libs hummingbird 1 3.12.13-3.hum1

red hat advisories RHSA-2026:8822RHSA-2026:8824RHSA-2026:7661RHSA-2026:7443RHSA-2026:3900RHSA-2026:3897

  • grafana Multi Linux Manager Tools SLE-15 12.4.10-150002.4.27.1
  • mgr-push Multi Linux Manager Tools SLE-15 5.2.5-150002.3.12.1
  • spacecmd Multi Linux Manager Tools SLE-15 5.2.10-150002.3.15.1
  • uyuni-tools Multi Linux Manager Tools SLE-Micro-5, Multi Linux Manager Tools SLE-15 5.2.17-150002.3.20.1
  • venv-salt-minion Multi Linux Manager Tools SLE-Micro-5, Multi Linux Manager Tools SLE-15 3006.0-150002.5.22.1
  • spacewalk-client-tools Multi Linux Manager Tools SLE-15 5.2.7-150002.3.12.1
  • golang-github-prometheus-prometheus Multi Linux Manager Tools SLE-15 3.13.2-150002.3.19.1
  • mgr-push Multi Linux Manager Tools SLE-12 5.2.5-120002.3.12.1

suse advisories SUSE-SU-2026:4585-1SUSE-SU-2026:4584-1SUSE-SU-2026:4583-1SUSE-SU-2026:4582-1SUSE-SU-2026:4581-1SUSE-SU-2026:4580-1

  • salt openSUSE Leap 16.0 3006.0-160000.4.1
  • salt-test openSUSE Leap 16.0 3006.0-160000.4.1
  • salt openSUSE Tumbleweed 3006.0-56.1
  • python313 openSUSE Leap 16.0 3.13.11-160000.1.1
  • python313-core openSUSE Leap 16.0 3.13.11-160000.1.1
  • python313-nogil openSUSE Leap 16.0 3.13.11-160000.1.1
  • python313-documentation openSUSE Leap 16.0 3.13.11-160000.1.1
  • python313-nogil-nogil-core openSUSE Leap 16.0 3.13.11-160000.1.1

opensuse advisories openSUSE-SU-2026:20412-1openSUSE-SU-2026:10389-1openSUSE-SU-2026:20081-1openSUSE-SU-2026:10011-1openSUSE-SU-2025:15849-1openSUSE-SU-2025:15850-1

  • python3.12 AlmaLinux 8 3.12.12-2.el8_10
  • python3.12-idle AlmaLinux 8 3.12.12-2.el8_10
  • python3.12-libs AlmaLinux 8 3.12.12-2.el8_10
  • python3.12-test AlmaLinux 8 3.12.12-2.el8_10
  • python3.12-tkinter AlmaLinux 8 3.12.12-2.el8_10
  • python3.12-rpm-macros AlmaLinux 8 3.12.12-2.el8_10
  • python-unversioned-command AlmaLinux 10 3.12.12-3.el10_1
  • python3.11 AlmaLinux 8 3.11.13-4.el8_10

almalinux advisories ALSA-2026:2419ALSA-2026:1828ALSA-2026:1374ALSA-2026:1408ALSA-2026:1410

  • python3.12 Rocky Linux 8 3.12.12-2.el8_10
  • python3.12 Rocky Linux 10 3.12.12-3.el10_1
  • python3.12 Rocky Linux 9 3.12.12-4.el9_7
  • python3.11 Rocky Linux 9 3.11.13-5.el9_7
  • python3.11 Rocky Linux 8 3.11.13-4.el8_10

rocky linux advisories RLSA-2026:2419RLSA-2026:1828RLSA-2026:1408RLSA-2026:1410RLSA-2026:1374

  • python3 Azure Linux 3.0 3.12.9-7

azure linux advisories AZL-71264

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-2025-13836 updated cvss 6.8

cpython: Excessive read buffering DoS in http.client

  • Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-cuda-rhel9, rhelai3/bootc-aws-cuda-rhel9, rhelai3/bootc-gcp-cuda-rhel9, rhelai3/bootc-azure-cuda-rhel9
    affected: workaround, no fix planned “Will not fix”
  • Red Hat AI Inference Server 3.3 rhaiis 1775680192, rhaiis 1775680262, rhaiis 1775749857, rhaiis 1778244546
    fixed: vendor fix RHSA-2026:8748
  • Red Hat CodeReady Linux Builder EUS (v.9.4) python3.11 3.11.7-1.el9_4.10, python3.12 3.12.1-4.el9_4.10, python3.11-idle 3.11.7-1.el9_4.10, python3.11-test 3.11.7-1.el9_4.10, python3.12-idle 3.12.1-4.el9_4.10, python3.12-test 3.12.1-4.el9_4.10, +2 more
    fixed: vendor fix RHSA-2026:1893
  • Red Hat CodeReady Linux Builder EUS (v.9.6) python3.12 3.12.9-1.el9_6.5, python3.11 3.11.11-2.el9_6.4, python3.12-idle 3.12.9-1.el9_6.5, python3.12-test 3.12.9-1.el9_6.5, python3.11-idle 3.11.11-2.el9_6.4, python3.11-test 3.11.11-2.el9_6.4, +2 more
    fixed: vendor fix RHSA-2026:1892
  • Red Hat Discovery 2 discovery 1769104765
    fixed: vendor fix RHSA-2026:1736
  • Red Hat Enterprise Linux AppStream (v. 8) python3.11 3.11.13-4.el8_10, python3.12 3.12.12-2.el8_10, python3.11-libs 3.11.13-4.el8_10, python3.12-libs 3.12.12-2.el8_10, python3.11-tkinter 3.11.13-4.el8_10, python3.12-tkinter 3.12.12-2.el8_10, +2 more
    fixed: vendor fix RHSA-2026:1374
  • Red Hat Enterprise Linux AppStream (v. 9) python3.11 3.11.13-5.el9_7, python3.12 3.12.12-4.el9_7, python3.11-libs 3.11.13-5.el9_7, python3.12-libs 3.12.12-4.el9_7, python3.11-tkinter 3.11.13-5.el9_7, python3.12-tkinter 3.12.12-4.el9_7
    fixed: vendor fix RHSA-2026:1410
  • Red Hat Enterprise Linux AppStream (v. 10) python3-tkinter 3.12.12-3.el10_1, python-unversioned-command 3.12.12-3.el10_1
    fixed: vendor fix RHSA-2026:1828
show 17 more
  • Red Hat Enterprise Linux AppStream E4S (v.8.8) python3.11 3.11.2-2.el8_8.7, python3.11-libs 3.11.2-2.el8_8.7, python3.11-tkinter 3.11.2-2.el8_8.7, python3.11-rpm-macros 3.11.2-2.el8_8.7
    fixed: vendor fix RHSA-2026:2084
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) python3.11 3.11.2-2.el9_2.9, python3.11-libs 3.11.2-2.el9_2.9, python3.11-tkinter 3.11.2-2.el9_2.9
    fixed: vendor fix RHSA-2026:1922
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) python3-tkinter 3.12.9-2.el10_0.6, python-unversioned-command 3.12.9-2.el10_0.6
    fixed: vendor fix RHSA-2026:2233
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) python3.11 3.11.7-1.el9_4.10, python3.12 3.12.1-4.el9_4.10, python3.11-libs 3.11.7-1.el9_4.10, python3.12-libs 3.12.1-4.el9_4.10, python3.11-tkinter 3.11.7-1.el9_4.10, python3.12-tkinter 3.12.1-4.el9_4.10
    fixed: vendor fix RHSA-2026:1893
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) python3.12 3.12.9-1.el9_6.5, python3.11 3.11.11-2.el9_6.4, python3.12-libs 3.12.9-1.el9_6.5, python3.11-libs 3.11.11-2.el9_6.4, python3.12-tkinter 3.12.9-1.el9_6.5, python3.11-tkinter 3.11.11-2.el9_6.4
    fixed: vendor fix RHSA-2026:1892
  • Red Hat Enterprise Linux AppStream TUS (v.8.8) python3.11 3.11.2-2.el8_8.7, python3.11-libs 3.11.2-2.el8_8.7, python3.11-tkinter 3.11.2-2.el8_8.7, python3.11-rpm-macros 3.11.2-2.el8_8.7
    fixed: vendor fix RHSA-2026:2084
  • Red Hat Enterprise Linux BaseOS (v. 10) python3 3.12.12-3.el10_1, python3.12 3.12.12-3.el10_1, python3-libs 3.12.12-3.el10_1
    fixed: vendor fix RHSA-2026:1828
  • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) python3 3.12.9-2.el10_0.6, python3.12 3.12.9-2.el10_0.6, python3-libs 3.12.9-2.el10_0.6
    fixed: vendor fix RHSA-2026:2233
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) python3.11 3.11.13-5.el9_7, python3.12 3.12.12-4.el9_7, python3.11-idle 3.11.13-5.el9_7, python3.11-test 3.11.13-5.el9_7, python3.12-idle 3.12.12-4.el9_7, python3.12-test 3.12.12-4.el9_7, +2 more
    fixed: vendor fix RHSA-2026:1410
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) python3-idle 3.12.12-3.el10_1, python3-test 3.12.12-3.el10_1
    fixed: vendor fix RHSA-2026:1828
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) python3-idle 3.12.9-2.el10_0.6, python3-test 3.12.9-2.el10_0.6
    fixed: vendor fix RHSA-2026:2233
  • Red Hat Enterprise Linux CRB (v. 8) python3.11 3.11.13-4.el8_10, python3.12 3.12.12-2.el8_10, python3.11-idle 3.11.13-4.el8_10, python3.11-test 3.11.13-4.el8_10, python3.12-idle 3.12.12-2.el8_10, python3.12-test 3.12.12-2.el8_10, +2 more
    fixed: vendor fix RHSA-2026:1374
  • Red Hat Hardened Images python3 3.14.4-1.hum1, python3.14 3.14.4-1.hum1, python3.11 3.11.15-4.hum1, python3.12 3.12.13-3.hum1, python3.13 3.13.13-1.hum1, python3-idle 3.14.4-1.hum1, +22 more
    fixed: vendor fix RHSA-2026:7661
  • Red Hat Update Infrastructure 5 rhui5 1770646925, rhui5 1770808765, rhui5 1773670073
    fixed: vendor fix RHSA-2026:4943
  • Red Hat Discovery 2 discovery 1769111774 Red Hat Enterprise Linux 6 python, tkinter, python-libs, python-test, python-tools Red Hat Enterprise Linux 7 python, firefox, python3, tkinter, python-libs, python-test, +5 more Red Hat Enterprise Linux 8 numpy, scipy, PyYAML, firefox, python3, mod_wsgi, +78 more Red Hat Enterprise Linux 9 firefox, python3, python3.9, firefox-x11, python3-idle, python3-libs, +3 more Red Hat Enterprise Linux 10 firefox
    +1 more products
    Red Hat Enterprise Linux AI (RHEL AI) rhelai1/bootc-amd-rhel9, rhelai1/bootc-nvidia-rhel9, rhelai1/bootc-azure-amd-rhel9, rhelai1/bootc-aws-nvidia-rhel9, rhelai1/bootc-gcp-nvidia-rhel9, rhelai1/bootc-azure-nvidia-rhel9
    not affected: vulnerable code not present
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-workbench-codeserver-datascience-cpu-py312-rhel9
    not affected: vulnerable code not in execute path
  • Red Hat OpenShift Dev Spaces devspaces/code-rhel9, devspaces/pluginregistry-rhel9, devspaces-tech-preview/idea-rhel9 Red Hat Update Infrastructure 5 rhui5 1770807477, rhui5 1770808689, rhui5 1773668803, rhui5 1773670137, rhui5 1773672059
    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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
11 mo ago

Exploit prediction

1.75% chance of exploitation in the next 30 days, higher than 77% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 6.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L
CNA 4.0 6.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L/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
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
bitnami libpython
<3.10.20
>=3.11.0, <3.11.15
>=3.12.0, <3.12.13
>=3.13.0, <3.13.11
>=3.14.0, <3.14.1
3.10.20
3.11.15
3.12.13
3.13.11
3.14.1
bitnami python
<3.10.20
>=3.11.0, <3.11.15
>=3.12.0, <3.12.13
>=3.13.0, <3.13.11
>=3.14.0, <3.14.1
3.10.20
3.11.15
3.12.13
3.13.11
3.14.1
bitnami python-min
<3.10.20
>=3.11.0, <3.11.15
>=3.12.0, <3.12.13
>=3.13.0, <3.13.11
>=3.14.0, <3.14.1
3.10.20
3.11.15
3.12.13
3.13.11
3.14.1

Affected products

  • Python Software Foundation CPython

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

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.