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high5.9

CVE-2023-43804

`Cookie` HTTP header isn't stripped on cross-origin redirects

Impact

urllib3 doesn't treat the `Cookie` HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. However, it is possible for a user to specify a `Cookie` header and unknowingly leak information via HTTP redirects to a different origin if that user doesn't disable redirects explicitly. Users **must** handle redirects themselves instead of relying on urllib3's automatic redirects to achieve safe processing of the `Cookie` header, thus we decided to strip the header by default in order to further protect users who aren't using the correct approach. ## Affected usages We believe the number of usages affected by this advisory is low. It requires all of the following to be true to be exploited: * Using an affected version of urllib3 (patched in v1.26.17 and v2.0.6) * Using the `Cookie` header on requests, which is mostly typical for impersonating a browser. * Not disabling HTTP redirects * Either not using HTTPS or for the origin server to redirect to a malicious origin. ## Remediation * Upgrading to at least urllib3 v1.26.17 or v2.0.6 * Disabling HTTP redirects using `redirects=False` when sending requests. * Not using the `Cookie` header.

Affected packages

EcosystemPackageAffectedFixed in
pipurllib3>= 2.0.0, < 2.0.62.0.6

Affected products

VendorProductAffected versions
PythonUrllib3
before 1.26.17
from 2.0.0 before 2.0.6
DebianDebian Linux
Version 10.0
FedoraprojectFedora
Versions 37, 38, 39

Weakness classification

CWE-200

References