{"id":"CVE-2026-21435","state":"PUBLISHED","title":"webtransport-go CloseWithError can block indefinitely","description":"webtransport-go is an implementation of the WebTransport protocol. Prior to v0.10.0, an attacker can cause a denial of service in webtransport-go by preventing or indefinitely delaying WebTransport session closure. A malicious peer can withhold QUIC flow control credit on the CONNECT stream, blocking transmission of the WT_CLOSE_SESSION capsule and causing the close operation to hang. This vulnerability is fixed in v0.10.0.","publishedAt":"2026-02-12T18:22:58.098Z","updatedAt":"2026-02-17T15:36:08.731Z","severity":{"score":5.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","source":"GitHub_M"},"assigner":"GitHub_M","products":["quic-go webtransport-go"],"affected":[{"vendor":"quic-go","product":"webtransport-go","versions":[{"version":"< 0.10.0","status":"affected"}]}],"references":["https://github.com/quic-go/webtransport-go/security/advisories/GHSA-px4r-g4p3-hhqv","https://github.com/quic-go/webtransport-go/releases/tag/v0.10.0"],"weaknesses":["CWE-400"],"ingestedAt":"2026-10-29T20:11:10.572Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/21xxx/CVE-2026-21435.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-21435","state":"PUBLISHED","datePublished":"2026-02-12T18:22:58.098Z","dateUpdated":"2026-02-17T15:36:08.731Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2025-12-29T03:00:29.275Z"},"containers":{"cna":{"title":"webtransport-go CloseWithError can block indefinitely","descriptions":[{"lang":"en","value":"webtransport-go is an implementation of the WebTransport protocol. Prior to v0.10.0, an attacker can cause a denial of service in webtransport-go by preventing or indefinitely delaying WebTransport session closure. A malicious peer can withhold QUIC flow control credit on the CONNECT stream, blocking transmission of the WT_CLOSE_SESSION capsule and causing the close operation to hang. This vulnerability is fixed in v0.10.0."}],"affected":[{"vendor":"quic-go","product":"webtransport-go","versions":[{"version":"< 0.10.0","status":"affected"}]}],"references":[{"url":"https://github.com/quic-go/webtransport-go/security/advisories/GHSA-px4r-g4p3-hhqv","name":"https://github.com/quic-go/webtransport-go/security/advisories/GHSA-px4r-g4p3-hhqv","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/quic-go/webtransport-go/releases/tag/v0.10.0","name":"https://github.com/quic-go/webtransport-go/releases/tag/v0.10.0","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":5.3,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-400","lang":"en","description":"CWE-400: Uncontrolled Resource Consumption","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-02-12T18:24:49.233Z"},"source":{"advisory":"GHSA-px4r-g4p3-hhqv","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-02-17T15:35:59.809407Z","id":"CVE-2026-21435","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-02-17T15:36:08.731Z"}}]}}}