When reusing a libcurl handle for sequential transfers driven by
environment-variable proxy configuration, libcurl fails to clear the proxy
authentication state between requests. Specifically, if the initial transfer
authenticates against proxyA using Digest auth, a subsequent transfer routed
through proxyB erroneously leaks the Proxy-Authorization: header intended
solely for proxyA.
{
"affects": "lib",
"package": "curl",
"CWE": {
"desc": "Authentication Bypass by Capture-replay",
"id": "CWE-294"
},
"www": "https://curl.se/docs/CVE-2026-8927.html",
"URL": "https://curl.se/docs/CVE-2026-8927.json",
"issue": "https://hackerone.com/reports/3744543",
"last_affected": "8.20.0",
"severity": "Medium"
}[
{
"signature_type": "Line",
"source": "https://github.com/curl/curl.git/commit/5c225384b8d52c67ce8259c6e4203bc57aacb567",
"signature_version": "v1",
"target": {
"file": "lib/urldata.h"
},
"id": "CURL-CVE-2026-8927-1a0c6a13",
"deprecated": false,
"digest": {
"line_hashes": [
"249901541397359699391036164270811196685",
"172078901768951523804103097952423731296",
"190570895038941515893744210575032446538",
"31498056193008689981868568994607611615"
],
"threshold": 0.9
}
},
{
"signature_type": "Function",
"source": "https://github.com/curl/curl.git/commit/5c225384b8d52c67ce8259c6e4203bc57aacb567",
"signature_version": "v1",
"target": {
"file": "lib/url.c",
"function": "url_set_conn_proxies"
},
"id": "CURL-CVE-2026-8927-536f3c2a",
"deprecated": false,
"digest": {
"function_hash": "291154372783688294644456481096551471603",
"length": 2977.0
}
},
{
"signature_type": "Function",
"source": "https://github.com/curl/curl.git/commit/5c225384b8d52c67ce8259c6e4203bc57aacb567",
"signature_version": "v1",
"target": {
"file": "lib/url.c",
"function": "Curl_close"
},
"id": "CURL-CVE-2026-8927-8e5a0f99",
"deprecated": false,
"digest": {
"function_hash": "108501742541011625610382809889759431245",
"length": 2235.0
}
},
{
"signature_type": "Line",
"source": "https://github.com/curl/curl.git/commit/5c225384b8d52c67ce8259c6e4203bc57aacb567",
"signature_version": "v1",
"target": {
"file": "lib/url.c"
},
"id": "CURL-CVE-2026-8927-f66aa01c",
"deprecated": false,
"digest": {
"line_hashes": [
"99719859570556904404521593072169703635",
"332982338190860309439232505874931661857",
"237740169298000483514266910350050489422",
"272304136448532278901451982226560871326",
"270501895432923960841663077836635145169",
"124922194065672035295929635149019045712",
"334857077174051218518059358584455468992",
"132974526410959760674586219544412541301"
],
"threshold": 0.9
}
}
]
"https://curl.se/docs/CURL-CVE-2026-8927.json"
"2026-06-24T08:07:05Z"