{"id":"EM-20261104-CMD7","url":"https://cyber.eventmonitor.net/incident/EM-20261104-CMD7/symfony-httpclient-vulnerability-cve-2026-121971/","type":"cve","title":"Symfony HttpClient Vulnerability (CVE-2026-121971)","subtitle":"CVE-2026-121971","subject":"CVE-2026-121971","status":"Developing","severity":"high","affected":[],"headline":null,"born":"2026-11-04T18:17:43.077Z","firstSignal":"2026-11-04T17:43:34.000Z","lastSignal":"2026-11-04T18:17:43.077Z","updated":"2026-11-07T00:59:45.971Z","revision":1,"life":[{"status":"Born","at":"2026-11-04T18:17:43.077Z","why":"second independent source: C6 NVD CVE API 2.0"},{"status":"Developing","at":"2026-11-04T18:17:43.077Z","why":"signals keep joining"}],"changeLog":[{"at":"2026-11-04T17:43:34.000Z","what":"First signal: C41 Red Hat Security Data"},{"at":"2026-11-04T18:17:43.077Z","what":"Born: second source, C6 NVD CVE API 2.0. Page EM-20261104-CMD7 created."}],"stages":[{"name":"Disclosed","at":"2026-11-04T18:17:43.077Z","detail":"C6 NVD published"},{"name":"Scored","at":"2026-11-04T18:17:43.077Z","detail":"CVSS 8.2 · EPSS 0.2%"},{"name":"Exploited","at":null,"detail":"No exploitation reported"},{"name":"Advisories","at":null,"detail":"None yet"},{"name":"Vendor Response","at":"2026-11-04T17:43:34.000Z","detail":"C41 published"},{"name":"Resolved","at":null,"detail":"After 14 quiet days"}],"signals":[{"at":"2026-11-04T17:43:34.000Z","source":"C41","sourceName":"Red Hat Security Data","role":"Vendor","severity":3,"title":"Red Hat: CVE-2026-121971 (important)","text":"symfony/http-client: symfony/http-client: Information disclosure via relative URL handling","url":"https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-121971.json"},{"at":"2026-11-04T18:17:43.077Z","source":"C6","sourceName":"NVD CVE API 2.0","role":"Database","severity":3,"title":"CVE-2026-121971 (CVSS 8.2)","text":"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.\n\n\n\nThe resolved URL falls outside the origin…","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121971"}],"crowd":[],"reference":{"nvd":{"published":"2026-11-04T18:17:43.077","score":8.2,"severity":"HIGH","desc":"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…","product":"","seen":1794008532627},"kev":null,"epss":{"epss":0.00249,"pct":0.16295,"at":1794013185971},"p0":false},"mergedInto":null,"publisher":"Event Monitor Cyber"}