{"cve":"CVE-2026-6253","nvd":{"published":"2026-05-13T13:01:56.570","modified":"2026-09-15T07:16:29.073","status":"Modified","description":"curl might erroneously pass on credentials for a first proxy to a second\nproxy.\n\nThis can happen when the following conditions are true:\n\n1. curl is setup to use specific different proxies for different URL schemes\n2. the first proxy needs credentials\n3. the second proxy uses no credentials\n4. while using the first proxy (using say `http://`), curl is asked to follow\n   a redirect to a URL using another scheme (say `https://`), accessed using a\n   second, different, proxy","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","score":5.9},"cwes":["CWE-522"],"references":["https://curl.se/docs/CVE-2026-6253.html","https://curl.se/docs/CVE-2026-6253.json","https://hackerone.com/reports/3669637","http://www.openwall.com/lists/oss-security/2026/04/29/11","https://hackerone.com/reports/3669637"],"products":["haxx:curl"],"source":"nvd","synced_at":"2026-10-19T22:35:16.954578616+00:00"},"epss":{"cve":"CVE-2026-6253","score":0.00719,"percentile":0.53923,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}