{"id":"CVE-2026-19931","summary":"Negotiate ambient user conn reuse","details":"A flaw in libcurl makes it wrongly reuse an HTTP connection setup for a given\nhostname using Negotiate authentication, when the initial request is done\nusing empty credentials. This can make user B's request get sent over user A's\npreviously authenticated connection.","aliases":["CURL-CVE-2026-19931"],"modified":"2026-09-13T03:45:48.540728971Z","published":"2026-09-06T17:47:43.523Z","related":["openSUSE-SU-2026:11696-1"],"database_specific":{"unresolved_ranges":[{"extracted_events":[{"introduced":"8.21.0"},{"last_affected":"8.21.0"},{"introduced":"8.20.0"},{"last_affected":"8.20.0"},{"introduced":"8.19.0"},{"last_affected":"8.19.0"},{"introduced":"8.18.0"},{"last_affected":"8.18.0"},{"introduced":"8.17.0"},{"last_affected":"8.17.0"},{"introduced":"8.16.0"},{"last_affected":"8.16.0"},{"introduced":"8.15.0"},{"last_affected":"8.15.0"},{"introduced":"8.14.1"},{"last_affected":"8.14.1"},{"introduced":"8.14.0"},{"last_affected":"8.14.0"},{"introduced":"8.13.0"},{"last_affected":"8.13.0"},{"introduced":"8.12.1"},{"last_affected":"8.12.1"},{"introduced":"8.12.0"},{"last_affected":"8.12.0"},{"introduced":"8.11.1"},{"last_affected":"8.11.1"},{"introduced":"8.11.0"},{"last_affected":"8.11.0"},{"introduced":"8.10.1"},{"last_affected":"8.10.1"},{"introduced":"8.10.0"},{"last_affected":"8.10.0"},{"introduced":"8.9.1"},{"last_affected":"8.9.1"},{"introduced":"8.9.0"},{"last_affected":"8.9.0"},{"introduced":"8.8.0"},{"last_affected":"8.8.0"},{"introduced":"8.7.1"},{"last_affected":"8.7.1"},{"introduced":"8.7.0"},{"last_affected":"8.7.0"},{"introduced":"8.6.0"},{"last_affected":"8.6.0"},{"introduced":"8.5.0"},{"last_affected":"8.5.0"},{"introduced":"8.4.0"},{"last_affected":"8.4.0"},{"introduced":"8.3.0"},{"last_affected":"8.3.0"},{"introduced":"8.2.1"},{"last_affected":"8.2.1"},{"introduced":"8.2.0"},{"last_affected":"8.2.0"},{"introduced":"8.1.2"},{"last_affected":"8.1.2"},{"introduced":"8.1.1"},{"last_affected":"8.1.1"},{"introduced":"8.1.0"},{"last_affected":"8.1.0"},{"introduced":"8.0.1"},{"last_affected":"8.0.1"},{"introduced":"8.0.0"},{"last_affected":"8.0.0"},{"introduced":"7.88.1"},{"last_affected":"7.88.1"},{"introduced":"7.88.0"},{"last_affected":"7.88.0"},{"introduced":"7.87.0"},{"last_affected":"7.87.0"},{"introduced":"7.86.0"},{"last_affected":"7.86.0"},{"introduced":"7.85.0"},{"last_affected":"7.85.0"},{"introduced":"7.84.0"},{"last_affected":"7.84.0"},{"introduced":"7.83.1"},{"last_affected":"7.83.1"},{"introduced":"7.83.0"},{"last_affected":"7.83.0"},{"introduced":"7.82.0"},{"last_affected":"7.82.0"},{"introduced":"7.81.0"},{"last_affected":"7.81.0"},{"introduced":"7.80.0"},{"last_affected":"7.80.0"},{"introduced":"7.79.1"},{"last_affected":"7.79.1"},{"introduced":"7.79.0"},{"last_affected":"7.79.0"},{"introduced":"7.78.0"},{"last_affected":"7.78.0"},{"introduced":"7.77.0"},{"last_affected":"7.77.0"},{"introduced":"7.76.1"},{"last_affected":"7.76.1"},{"introduced":"7.76.0"},{"last_affected":"7.76.0"},{"introduced":"7.75.0"},{"last_affected":"7.75.0"},{"introduced":"7.74.0"},{"last_affected":"7.74.0"},{"introduced":"7.73.0"},{"last_affected":"7.73.0"},{"introduced":"7.72.0"},{"last_affected":"7.72.0"},{"introduced":"7.71.1"},{"last_affected":"7.71.1"},{"introduced":"7.71.0"},{"last_affected":"7.71.0"},{"introduced":"7.70.0"},{"last_affected":"7.70.0"},{"introduced":"7.69.1"},{"last_affected":"7.69.1"},{"introduced":"7.69.0"},{"last_affected":"7.69.0"},{"introduced":"7.68.0"},{"last_affected":"7.68.0"},{"introduced":"7.67.0"},{"last_affected":"7.67.0"},{"introduced":"7.66.0"},{"last_affected":"7.66.0"},{"introduced":"7.65.3"},{"last_affected":"7.65.3"},{"introduced":"7.65.2"},{"last_affected":"7.65.2"},{"introduced":"7.65.1"},{"last_affected":"7.65.1"},{"introduced":"7.65.0"},{"last_affected":"7.65.0"},{"introduced":"7.64.1"},{"last_affected":"7.64.1"}],"source":"AFFECTED_FIELD"}],"cna_assigner":"curl","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/19xxx/CVE-2026-19931.json"},"references":[{"type":"WEB","url":"https://curl.se/docs/CVE-2026-19931.html"},{"type":"WEB","url":"https://curl.se/docs/CVE-2026-19931.json"},{"type":"WEB","url":"https://hackerone.com/reports/3923520"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/19xxx/CVE-2026-19931.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-19931"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/curl/curl","events":[{"introduced":"521bbbe29928f9bc1c61306df612e856d45cbe5a"},{"fixed":"01346829096c61b372692f6dc43ffa778c6caccd"}],"database_specific":{"extracted_events":[{"introduced":"7.64.1"},{"fixed":"8.22.0"}],"source":"CPE_RANGE","cpe":"cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*"}}],"versions":["rc-8_22_0-3","rc-8_22_0-2","rc-8_22_0-1","curl-8_21_0","rc-8_21_0-3","rc-8_21_0-2","rc-8_21_0-1","curl-8_20_0","rc-8_20_0-3","rc-8_20_0-2","rc-8_20_0-1","curl-8_19_0","rc-8_19_0-3","rc-8_19_0-2","rc-8_19_0-1","curl-8_18_0","rc-8_18_0-3","rc-8_18_0-2","rc-8_18_0-1","curl-8_17_0","curl-8_16_0","curl-8_15_0","curl-8_14_1","curl-8_14_0","curl-8_13_0","curl-8_12_1","curl-8_12_0","curl-8_11_1","curl-8_11_0","curl-8_10_1","curl-8_10_0","curl-8_9_1","curl-8_9_0","curl-8_8_0","curl-8_7_1","curl-8_7_0","curl-8_6_0","curl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