{"cve":"CVE-2026-55568","nvd":{"published":"2026-06-23T16:17:02.990","modified":"2026-06-26T19:34:13.833","status":"Analyzed","description":"Guzzle is an extensible PHP HTTP client. Prior to 7.12.1, in certain configurations, traffic expected to be protected by TLS on the hop to the proxy is transmitted in cleartext. Proxy authentication credentials (the Proxy-Authorization header, proxy userinfo in the proxy URL, or CURLOPT_PROXYUSERPWD) are sent without encryption, and the CONNECT target host and port for tunneled HTTPS requests are exposed. The built-in cURL handlers (GuzzleHttp\\Handler\\CurlHandler and GuzzleHttp\\Handler\\CurlMultiHandler, used by default whenever the PHP cURL extension is available) accept an https:// proxy. libcurl older than 7.50.2 silently treats an https:// proxy as a plaintext http:// proxy. The TLS connection to the proxy is never established, and the proxy leg is cleartext with no error or warning. An application is affected when it sends requests through one of the built-in cURL handlers, configures an https:// proxy expecting the proxy connection itself to be encrypted, and runs with libcurl older than 7.50.2. This vulnerability is fixed in 7.12.1.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","score":5.9},"cwes":["CWE-311","CWE-319","CWE-636"],"references":["https://github.com/guzzle/guzzle/security/advisories/GHSA-wpwq-4j6v-78m3"],"products":["guzzlephp:guzzle"],"source":"nvd","synced_at":"2026-10-19T22:39:28.638635428+00:00"},"epss":{"cve":"CVE-2026-55568","score":0.00148,"percentile":0.0396,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-wpwq-4j6v-78m3","url":"https://osv.dev/vulnerability/GHSA-wpwq-4j6v-78m3","summary":"guzzlehttp/guzzle: Silent HTTPS-Proxy Downgrade to Cleartext","modified":"2026-09-10T03:50:50.904385747Z","packages":[{"ecosystem":"Packagist","name":"guzzlehttp/guzzle","purl":"pkg:composer/guzzlehttp/guzzle","ranges":["<7.12.1"],"fixed":["7.12.1"]}]}],"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."]}