{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-86252", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "state": "PUBLISHED", "assignerShortName": "VulnCheck", "dateReserved": "2026-09-06T11:35:19.316Z", "datePublished": "2026-09-06T12:00:27.561Z", "dateUpdated": "2026-09-06T12:00:27.561Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-09-06T12:00:27.561Z"}, "datePublic": "2026-03-20T00:00:00.000Z", "title": "h3 before 1.15.9 SSE Event Injection via Carriage Return", "descriptions": [{"lang": "en", "value": "h3 versions before 1.15.9 fail to sanitize carriage return characters in EventStream data and comment fields, allowing attackers to inject arbitrary SSE events by including unsanitized carriage returns. Attackers can inject event type directives, split single push calls into multiple browser-parsed events, or escape comment fields to inject data, bypassing the prior CVE fix that only addressed newline injection."}], "problemTypes": [{"descriptions": [{"lang": "en", "description": "Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')", "cweId": "CWE-74", "type": "CWE"}]}], "affected": [{"vendor": "h3js", "product": "h3", "defaultStatus": "unaffected", "packageURL": "pkg:npm/h3", "versions": [{"version": "0", "status": "affected", "lessThan": "1.15.9", "versionType": "semver"}, {"version": "1.15.9", "status": "unaffected", "versionType": "semver"}, {"version": "2.0.0-beta.0", "status": "affected", "lessThan": "2.0.1-rc.17", "versionType": "semver"}, {"version": "2.0.1-rc.17", "status": "unaffected", "versionType": "semver"}]}], "metrics": [{"format": "CVSS", "cvssV4_0": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "baseScore": 6.9, "baseSeverity": "MEDIUM"}}, {"format": "CVSS", "cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "NONE", "baseScore": 5.3, "baseSeverity": "MEDIUM"}}], "references": [{"url": "https://github.com/h3js/h3/security/advisories/GHSA-4hxc-9384-m385", "tags": ["vendor-advisory"], "name": "GitHub Security Advisory (GHSA-4hxc-9384-m385)"}, {"name": "VulnCheck Advisory: h3 before 1.15.9 SSE Event Injection via Carriage Return", "tags": ["third-party-advisory"], "url": "https://www.vulncheck.com/advisories/h3-before-1.15.9-sse-event-injection-via-carriage-return"}], "credits": [{"lang": "en", "value": "offset", "type": "reporter"}], "x_generator": {"engine": "vulncheck-endgame"}}}}

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{}

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