CVE-2025-13836
Excessive read buffering DoS in http.client
- State
- Published
- Severity
- 6.3 Medium
- Published
- Dec 1, 2025
- Updated
- Mar 3, 2026
- Reserved
- Dec 1, 2025
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.3 Medium | 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 | PSF |
Weaknesses
- CWE-400 Uncontrolled Resource Consumption
Affected Products
| Product | Versions |
|---|---|
CPythonPython Software Foundation |
|
References
- https://github.com/python/cpython/issues/119451issue-tracking
- https://github.com/python/cpython/pull/119454patch
- https://github.com/python/cpython/commit/4ce27904b597c77d74dd93f2c912676021a99155patch
- https://github.com/python/cpython/commit/5a4c4a033a4a54481be6870aa1896fad732555b5patch
- https://mail.python.org/archives/list/security-announce@python.org/thread/OQ6G7MKRQIS3OAREC3HNG3D2DPOU34XO/vendor-advisory
- https://github.com/python/cpython/commit/289f29b0fe38baf2d7cb5854f4bb573cc34a6a15patch
- https://github.com/python/cpython/commit/14b1fdb0a94b96f86fc7b86671ea9582b8676628patch
- https://github.com/python/cpython/commit/5dc101675fd22918facbbe0fecdc821502beaaf0patch
- https://github.com/python/cpython/commit/afc40bdd3dd71f343fd9016f6d8eebbacbd6587cpatch
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