When using an ambient user in a first transfer doing Negotiate authentication and asked to follow redirects, curl could pass on its credential details to an unrelated second origin when asked to redirect there.
{
"CWE": {
"desc": "Information Exposure Through Sent Data",
"id": "CWE-201"
},
"URL": "https://curl.se/docs/CVE-2026-86413.json",
"affects": "both",
"issue": "https://hackerone.com/reports/3993549",
"last_affected": "8.22.0",
"package": "curl",
"severity": "Low",
"www": "https://curl.se/docs/CVE-2026-86413.html"
}"https://curl.se/docs/CURL-CVE-2026-86413.json"
[
{
"deprecated": false,
"digest": {
"function_hash": "197484543705449537405576979917654205683",
"length": 1414
},
"id": "CURL-CVE-2026-86413-1e93bc7f",
"signature_type": "Function",
"signature_version": "v1",
"source": "https://github.com/curl/curl.git/commit/43029e2ec37eba2354ced199ccd8898de695858e",
"target": {
"file": "lib/url.c",
"function": "url_attach_existing"
}
},
{
"deprecated": false,
"digest": {
"line_hashes": [
"187364918574459101311412106745538592488",
"264975616631119401330704202978605564609",
"317586723021531035471710209410329204294",
"191577447307436254778621372265599242980",
"177312209620819793276913791421236844650",
"137629164407106226757418211430020627125",
"41976915244105234222538516649574510234",
"23352433916399309512248611259609034193"
],
"threshold": 0.9
},
"id": "CURL-CVE-2026-86413-cdc88345",
"signature_type": "Line",
"signature_version": "v1",
"source": "https://github.com/curl/curl.git/commit/43029e2ec37eba2354ced199ccd8898de695858e",
"target": {
"file": "lib/url.c"
}
}
]
"2026-10-14T07:04:25Z"