The component ScopingHttpClient in Symfony HttpClient merges the options of its default scope (such as authbearer or authbasic) into a…
CVE-2026-121971
The component ScopingHttpClient in Symfony HttpClient merges the options of its default scope (such as authbearer or authbasic) into a request before resolving a relative URL against the baseuri, 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 baseuri and credentials, including those created with HttpClient::createForBaseUri() or configured under framework.httpclient.scopedclients. 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…
Assessment
- CVSS
- 8.2 (v4.0)
- Severity
- High
- Known exploited
- Not listed in CISA KEV
- Exploit availability
- Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
- Published
- 4 November 2026
- Last updated
- 5 November 2026
- Affected
- sensiolabs · symfony
- Assigner
- Checkmarx
CVSS vectorCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
At the source
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