Python: Excessive read buffering DoS in http.client (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.
AI Analysis
Technical Summary
The vulnerability CVE-2025-13836 involves excessive read buffering in the cpython http.client module, which can lead to a denial of service condition. This issue is addressed by Red Hat in an update to python3.12 packages for Red Hat Enterprise Linux 9.6 Extended Update Support and related product variants. The advisory rates the security impact as moderate. No CVSS score is provided in the advisory. The fix is included in python3.12 version 3.12.9-1.el9_6.5 packages. The vulnerability relates to improper resource allocation (CWE-770) that could be exploited to cause service disruption.
Potential Impact
Successful exploitation of this vulnerability could cause a denial of service by exhausting resources through excessive read buffering in the http.client module of Python 3.12. This could disrupt applications or services relying on this Python version. There are no known exploits in the wild at this time. The impact is rated moderate by Red Hat Product Security.
Mitigation Recommendations
Red Hat has released an official security update for python3.12 packages that addresses this vulnerability. Users of affected Red Hat Enterprise Linux 9.6 Extended Update Support and related variants should apply the python3.12 update to version 3.12.9-1.el9_6.5 or later as provided by Red Hat. Refer to Red Hat article https://access.redhat.com/articles/11258 for update instructions. No additional mitigation is required beyond applying the official patch.
Python: Excessive read buffering DoS in http.client (CVE-2025-13836)
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.
Affected software
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability CVE-2025-13836 involves excessive read buffering in the cpython http.client module, which can lead to a denial of service condition. This issue is addressed by Red Hat in an update to python3.12 packages for Red Hat Enterprise Linux 9.6 Extended Update Support and related product variants. The advisory rates the security impact as moderate. No CVSS score is provided in the advisory. The fix is included in python3.12 version 3.12.9-1.el9_6.5 packages. The vulnerability relates to improper resource allocation (CWE-770) that could be exploited to cause service disruption.
Potential Impact
Successful exploitation of this vulnerability could cause a denial of service by exhausting resources through excessive read buffering in the http.client module of Python 3.12. This could disrupt applications or services relying on this Python version. There are no known exploits in the wild at this time. The impact is rated moderate by Red Hat Product Security.
Mitigation Recommendations
Red Hat has released an official security update for python3.12 packages that addresses this vulnerability. Users of affected Red Hat Enterprise Linux 9.6 Extended Update Support and related variants should apply the python3.12 update to version 3.12.9-1.el9_6.5 or later as provided by Red Hat. Refer to Red Hat article https://access.redhat.com/articles/11258 for update instructions. No additional mitigation is required beyond applying the official patch.
Technical Details
- Gcve Source
- db.gcve.eu
- Csaf Category
- csaf_security_advisory
- Csaf Version
- 2.0
- Publisher
- Red Hat Product Security
- Advisory Id
- RHSA-2026:3900
- Cve Count
- 1
Threat ID: 6a3da1c34853345fc181eb23
Added to database: 06/25/2026, 21:46:43 UTC
Last enriched: 06/25/2026, 21:55:18 UTC
Last updated: 09/10/2026, 19:36:49 UTC
Views: 21
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