Resource exhaustion in Python
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.
Vulnerability class: DoS (Denial of Service)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.016 (75.3th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 75th percentile — 75.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.016 · newest: 0.016 · change: 0.000
Affected products
- Python — versions 3.14.0, 3.15.0
- Python Software Foundation Cpython — versions 0, 3.11.0, 3.12.0
Weakness classification (CWE)
References
- github.com/python/cpython/issues/119451 (issue-tracking, Patch, Issue Tracking)
- github.com/python/cpython/pull/119454 (Patch, patch, Issue Tracking)
- github.com/python/cpython/commit/4ce27904b597c77d74dd93f2c912676021a99155 (Patch, patch)
- github.com/python/cpython/commit/5a4c4a033a4a54481be6870aa1896fad732555b5 (Patch, patch)
- mail.python.org/archives/list/security-announce@python.org/thread/OQ6G7MKRQIS3O… (vendor-advisory, Vendor Advisory)
- github.com/python/cpython/commit/289f29b0fe38baf2d7cb5854f4bb573cc34a6a15 (Patch, patch)
- github.com/python/cpython/commit/14b1fdb0a94b96f86fc7b86671ea9582b8676628 (Patch, patch)
- github.com/python/cpython/commit/5dc101675fd22918facbbe0fecdc821502beaaf0 (Patch, patch)
- github.com/python/cpython/commit/afc40bdd3dd71f343fd9016f6d8eebbacbd6587c (Patch, patch)
Frequently asked questions
- What is CVE-2025-13836?
- CVE-2025-13836 is a high-severity vulnerability in Python, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2025-12-01.
- How severe is CVE-2025-13836?
- High severity. CVSS v3 base score is 7.5 out of 10.