CVE-2026-6253 — proxy credentials leak over redirect-to proxy
curl might erroneously pass on credentials for a first proxy to a second proxy. This can happen when the following conditions are true: 1. curl is setup to use specific differ…
Published: 2026-05-13 · CVSS: 5.9 · CVSS 3.1
curl might erroneously pass on credentials for a first proxy to a second proxy. This can happen when the following conditions are true: 1. curl is setup to use specific different proxies for different URL schemes 2. the first proxy needs credentials 3. the second proxy uses no credentials 4. while using the first proxy (using say `http://`), curl is asked to follow a redirect to a URL using another scheme (say `https://`), accessed using a second, different, proxy
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7