{"id":"CVE-2026-6276","title":"Using libcurl, when a custom `Host:` header is first set for an HTTP request\nand a second request is subsequently done using the same *easy handle* but\nwithout the custom `Host:` header set, the second request would use stale\ninformation…","summary":"Using libcurl, when a custom `Host:` header is first set for an HTTP request\nand a second request is subsequently done using the same *easy handle* but\nwithout the custom `Host:` header set, the second request would use stale\ninformation…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-346","CWE-319"],"vendor":"haxx","product":"curl","affected":["curl >= 7.71.0, < 8.20.0"],"patched":["curl 8.20.0"],"published":"2026-05-13","updated":"2026-09-15","sourceUpdated":"2026-09-15T07:16:29.343","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-6276","references":[{"url":"https://curl.se/docs/CVE-2026-6276.html","label":"2499f714-1537-4658-8207-48ae4bb9eae9"},{"url":"https://curl.se/docs/CVE-2026-6276.json","label":"2499f714-1537-4658-8207-48ae4bb9eae9"},{"url":"https://hackerone.com/reports/3671818","label":"2499f714-1537-4658-8207-48ae4bb9eae9"},{"url":"http://www.openwall.com/lists/oss-security/2026/04/29/13","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://hackerone.com/reports/3671818","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-6276.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-6276"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2461203"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-6276"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-6276"},{"url":"https://access.redhat.com/errata/RHSA-2026:12916"}],"tags":["nvd","cve.org","exploit-available","csaf","vex","red-hat","score-dispute"],"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"yes","technicalImpact":"partial","timestamp":"2026-05-13T17:24:29.094167Z"},"epss":0.00295,"epssPercentile":0.22298,"ingestedAt":"2026-09-15T07:33:29.266Z","scores":{"nvd":7.5,"vendor":3.7},"slug":"CVE-2026-6276","body":"## Overview\n\nUsing libcurl, when a custom `Host:` header is first set for an HTTP request\nand a second request is subsequently done using the same *easy handle* but\nwithout the custom `Host:` header set, the second request would use stale\ninformation and pass on cookies meant for the first host in the second\nrequest. Leak them.\n\n## Affected\n\n- `curl >= 7.71.0, < 8.20.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `curl 8.20.0`\n\n## Vendor advisories\n\n- **RHSA-2026:12916** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-05-02 · [advisory](https://access.redhat.com/errata/RHSA-2026:12916)\n- **Red Hat VEX** · Low · affected: Confidential Compute Attestation, Logging Subsystem for Red Hat OpenShift, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · no fix planned: Confidential Compute Attestation, Logging Subsystem for Red Hat OpenShift, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, … · updated 2026-09-15 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-6276.json)","depth":"midnight","depthScore":53,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[]}