CVE-2026-97689

urllib3 is an HTTP client library for Python. From 1.10.3 until 2.8.0, the HTTPResponse.read_chunked and HTTPResponse.stream methods can allocate unbounded memory because the streaming chunk parser buffers the chunk-size field until newline or EOF without a length bound. The trigger is that a malicious server returns Transfer-Encoding: chunked followed by a very long run of bytes without a newline. The attack mechanism is that a malicious HTTP server sends a very long unterminated chunk-size line. The impact is that unbounded memory allocation can exhaust the client process. This issue is fixed in version 2.8.0.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/urllib3/urllib3/commit/cd770b059b543be29298ea5c52afb0b1b090f5ed	Patch
https://github.com/urllib3/urllib3/releases/tag/2.8.0	Release Notes
https://github.com/urllib3/urllib3/security/advisories/GHSA-vxq7-64xx-v4gw	Mitigation Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:python:urllib3:*:*:*:*:*:*:*:*

History

13 Oct 2026, 20:20

Type	Values Removed	Values Added
References	~~() https://github.com/urllib3/urllib3/commit/cd770b059b543be29298ea5c52afb0b1b090f5ed -~~	() https://github.com/urllib3/urllib3/commit/cd770b059b543be29298ea5c52afb0b1b090f5ed - Patch
References	~~() https://github.com/urllib3/urllib3/releases/tag/2.8.0 -~~	() https://github.com/urllib3/urllib3/releases/tag/2.8.0 - Release Notes
References	~~() https://github.com/urllib3/urllib3/security/advisories/GHSA-vxq7-64xx-v4gw -~~	() https://github.com/urllib3/urllib3/security/advisories/GHSA-vxq7-64xx-v4gw - Mitigation, Vendor Advisory
First Time		Python urllib3 Python
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 7.5
CPE		cpe:2.3:a:python:urllib3::::::::

29 Sep 2026, 16:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-09-29 16:17

Updated : 2026-10-13 20:20

NVD link : CVE-2026-97689

Mitre link : CVE-2026-97689

CVE.ORG link : CVE-2026-97689

JSON object : View

Products Affected

python

urllib3

CWE

CWE-770

Allocation of Resources Without Limits or Throttling

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