{"id":"CVE-2026-5545","summary":"wrong reuse of HTTP Negotiate connection","details":"libcurl might in some circumstances reuse the wrong connection when asked to\ndo an authenticated HTTP(S) request after a Negotiate-authenticated one, when\nboth use the same host.\n\nlibcurl features a pool of recent connections so that subsequent requests can\nreuse an existing connection to avoid overhead.\n\nWhen reusing a connection a range of criteria must be met. Due to a logical\nerror in the code, a request that was issued by an application could\nwrongfully reuse an existing connection to the same server that was\nauthenticated using different credentials.\n\nAn application that first uses Negotiate authentication to a server with\n`user1:password1` and then does another operation to the same server asking\nfor any authentication method but for `user2:password2` (while the previous\nconnection is still alive) - the second request gets confused and wrongly\nreuses the same connection and sends the new request over that connection\nthinking it uses a mix of user1's and user2's credentials when it is in fact\nstill using the connection authenticated for user1...","aliases":["CURL-CVE-2026-5545"],"modified":"2026-09-17T03:30:46.199409443Z","published":"2026-05-13T08:27:26.065Z","related":["SUSE-SU-2026:1717-1","SUSE-SU-2026:1940-1","SUSE-SU-2026:21452-1","SUSE-SU-2026:22146-1","SUSE-SU-2026:22156-1","SUSE-SU-2026:2703-1","SUSE-SU-2026:3798-1","openSUSE-SU-2026:10674-1","openSUSE-SU-2026:20973-1"],"database_specific":{"cna_assigner":"curl","cwe_ids":["CWE-305"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/5xxx/CVE-2026-5545.json","unresolved_ranges":[{"source":"AFFECTED_FIELD","extracted_events":[{"introduced":"7.10.6"},{"fixed":"8.14.2"},{"introduced":"8.15.0"},{"fixed":"8.16.1"},{"introduced":"e56ae1426cb7a0a4a427cf8d6099a821fdaae428"},{"fixed":"33e43985b8f3b9e66691d06e70be0395849856cd"}]}]},"references":[{"type":"WEB","url":"https://curl.se/docs/CVE-2026-5545.html"},{"type":"WEB","url":"https://curl.se/docs/CVE-2026-5545.json"},{"type":"WEB","url":"https://hackerone.com/reports/3642555"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/5xxx/CVE-2026-5545.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-5545"},{"type":"PACKAGE","url":"https://github.com/curl/curl.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/curl/curl","events":[{"introduced":"bdb5e5a25037a585e0ec6b83d29b25961c6823f8"},{"fixed":"6e3f8dc1f173b47de9a68516ce4b95bf25598c2f"}],"database_specific":{"source":"CPE_RANGE","cpe":"cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"7.10.6"},{"fixed":"8.20.0"}]}}],"versions":["7.10.6","7.10.7","7.10.8","7.11.0","7.11.1","7.11.2","7.12.0","7.12.1","7.12.2","7.12.3","7.13.0","7.13.1","7.13.2","7.14.0","7.14.1","7.15.0","7.15.1","7.15.2","7.15.3","7.15.4","7.15.5","7.16.0","7.16.1","7.16.2","7.16.3","7.16.4","7.17.0","7.17.1","7.18.0","7.18.1","7.18.2","7.19.0","7.19.1","7.19.2","7.19.3","7.19.4","7.19.5","7.19.6","7.19.7","7.20.0","7.20.1","7.21.0","7.21.1","7.21.2","7.21.3","7.21.4","7.21.5","7.21.6","7.21.7","7.22.0","7.23.0","7.23.1","7.24.0","7.25.0","7.26.0","7.27.0","7.28.0","7.28.1","7.29.0","7.30.0","7.31.0","7.32.0","7.33.0","7.34.0","7.35.0","7.36.0","7.37.0","7.37.1","7.38.0","7.39.0","7.40.0","7.41.0","7.42.0","7.42.1","7.43.0","7.44.0","7.45.0","7.46.0","7.47.0","7.47.1","7.48.0","7.49.0","7.49.1","7.50.0","7.50.1","7.50.2","7.50.3","7.51.0","7.52.0","7.52.1","7.53.0","7.53.1","7.54.0","7.54.1","7.55.0","7.55.1","7.56.0","7.56.1","7.57.0","7.58.0","7.59.0","7.60.0","7.61.0","7.61.1","7.62.0","7.63.0","7.64.0","7.64.1","7.65.0","7.65.1","7.65.2","7.65.3","7.66.0","7.67.0","7.68.0","7.69.0","7.69.1","7.70.0","7.71.0","7.71.1","7.72.0","7.73.0","7.74.0","7.75.0","7.76.0","7.76.1","7.77.0","7.78.0","7.79.0","7.79.1","7.80.0","7.81.0","7.82.0","7.83.0","7.83.1","7.84.0","7.85.0","7.86.0","7.87.0","7.88.0","7.88.1","8.0.0","8.0.1","8.1.0","8.1.1","8.1.2","8.10.0","8.10.1","8.11.0","8.11.1","8.12.0","8.12.1","8.13.0","8.14.0","8.14.1","8.15.0","8.16.0","8.18.0","8.19.0","8.2.0","8.2.1","8.3.0","8.4.0","8.5.0","8.6.0","8.7.0","8.7.1","8.8.0","8.9.0","8.9.1"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-5545.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N"}]}