CVE-2025-13836

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.

CVSS v3 9.1 CRITICAL

9.1^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/python/cpython/commit/14b1fdb0a94b96f86fc7b86671ea9582b8676628	Patch
https://github.com/python/cpython/commit/289f29b0fe38baf2d7cb5854f4bb573cc34a6a15	Patch
https://github.com/python/cpython/commit/4ce27904b597c77d74dd93f2c912676021a99155	Patch
https://github.com/python/cpython/commit/5a4c4a033a4a54481be6870aa1896fad732555b5	Patch
https://github.com/python/cpython/commit/5dc101675fd22918facbbe0fecdc821502beaaf0
https://github.com/python/cpython/commit/afc40bdd3dd71f343fd9016f6d8eebbacbd6587c
https://github.com/python/cpython/issues/119451	Issue Tracking Patch
https://github.com/python/cpython/pull/119454	Issue Tracking Patch
https://mail.python.org/archives/list/security-announce@python.org/thread/OQ6G7MKRQIS3OAREC3HNG3D2DPOU34XO/	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:python:python::::::::
	cpe:2.3:a:python:python:3.14.0:-::::::
	cpe:2.3:a:python:python:3.15.0:alpha1::::::
	cpe:2.3:a:python:python:3.15.0:alpha2::::::

History

No history.

Information

Published : 2025-12-01 18:16

Updated : 2026-01-26 15:16

NVD link : CVE-2025-13836

Mitre link : CVE-2025-13836

CVE.ORG link : CVE-2025-13836

JSON object : View

Products Affected

python

python

CWE

CWE-125

Out-of-bounds Read

CWE-400

Uncontrolled Resource Consumption

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This allows a malicious server to cause the client to read large amounts of data into memory, potentially causing OOM or other DoS."}, {"lang": "es", "value": "Al leer una respuesta HTTP de un servidor, si no se especifica una cantidad de lectura, el comportamiento predeterminado ser\u00e1 usar Content-Length. Esto permite a un servidor malicioso hacer que el cliente lea grandes cantidades de datos en la memoria, lo que podr\u00eda causar OOM u otro DoS."}], "lastModified": "2026-01-26T15:16:06.210", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:python:python:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "701E94DB-563E-44FF-AABF-0F49A9FF664A", "versionEndExcluding": "3.13.11"}, {"criteria": "cpe:2.3:a:python:python:3.14.0:-:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "D9A884CF-F98D-490D-A3B6-74F0DBFC3BD3"}, {"criteria": "cpe:2.3:a:python:python:3.15.0:alpha1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "A3327507-0B1D-4F28-A983-D07A2C8A7696"}, {"criteria": "cpe:2.3:a:python:python:3.15.0:alpha2:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "C8AF17F1-A27F-4C98-BA5A-B4319710E8D1"}], "operator": "OR"}]}], "sourceIdentifier": "cna@python.org"}