Description
The component ScopingHttpClient in Symfony HttpClient merges the options of its default scope (such as auth_bearer or auth_basic) into a request before resolving a relative URL against the base_uri, allowing a network-path reference such as "//evil.example/steal" to be sent to another origin together with the default scope’s credentials, and resulting in potential disclosure of those credentials to an attacker-controlled server. This affects Symfony in versions 5.x prior to 5.4.56, 6.x prior to 6.4.50, 7.x prior to 7.4.23, and 8.x prior to 8.1.11.



The resolved URL falls outside the origin of the base URI, yet it keeps the merged options, whereas the absolute spelling "https://evil.example/steal" receives none. The same happens with a different port or user-info part on the same host.









This is reachable whenever an attacker controls the beginning of a URL passed to a client built with a base_uri and credentials, including those created with HttpClient::createForBaseUri() or configured under framework.http_client.scoped_clients.

To solve the issue, after resolving a relative URL against the base URI of the default scope, ScopingHttpClient now compares the scheme and authority of the result with those of the base URI, parsed the way the request is sent.
Published: 2026-11-04
Score: 8.2 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

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History

Wed, 04 Nov 2026 18:00:00 +0000

Type Values Removed Values Added
Description The component ScopingHttpClient in Symfony HttpClient merges the options of its default scope (such as auth_bearer or auth_basic) into a request before resolving a relative URL against the base_uri, allowing a network-path reference such as "//evil.example/steal" to be sent to another origin together with the default scope’s credentials, and resulting in potential disclosure of those credentials to an attacker-controlled server. This affects Symfony in versions 5.x prior to 5.4.56, 6.x prior to 6.4.50, 7.x prior to 7.4.23, and 8.x prior to 8.1.11. The resolved URL falls outside the origin of the base URI, yet it keeps the merged options, whereas the absolute spelling "https://evil.example/steal" receives none. The same happens with a different port or user-info part on the same host. This is reachable whenever an attacker controls the beginning of a URL passed to a client built with a base_uri and credentials, including those created with HttpClient::createForBaseUri() or configured under framework.http_client.scoped_clients. To solve the issue, after resolving a relative URL against the base URI of the default scope, ScopingHttpClient now compares the scheme and authority of the result with those of the base URI, parsed the way the request is sent.
Title Symfony: ScopingHttpClient Sends the Credentials of Its Default Scope to Other Origins Through Network-Path References
First Time appeared Sensiolabs
Sensiolabs symfony
Weaknesses CWE-200
CWE-522
CPEs cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
Vendors & Products Sensiolabs
Sensiolabs symfony
References
Metrics cvssV4_0

{'score': 8.2, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'}


Subscriptions

Sensiolabs Symfony
cve-icon MITRE

Status: PUBLISHED

Assigner: Checkmarx

Published:

Updated: 2026-11-04T17:43:34.806Z

Reserved: 2026-11-04T13:03:55.851Z

Link: CVE-2026-121971

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-11-04T18:17:43.077

Modified: 2026-11-04T18:17:43.077

Link: CVE-2026-121971

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-11-04T22:00:16Z

Weaknesses
  • CWE-200

    Exposure of Sensitive Information to an Unauthorized Actor

  • CWE-522

    Insufficiently Protected Credentials