{"affected":[{"defaultStatus":"unaffected","product":"tokio-quiche","source":"CNA: cloudflare","vendor":"Cloudflare","versions":[{"lessThanOrEqual":"0.20.1","status":"affected","version":"0.0.1","versionType":"semver"}]}],"cveId":"CVE-2026-12708","cwes":["CWE-401"],"description":"Summary\n\n\nCloudflare tokio-quiche was found to contain an uncontrolled resource consumption vulnerability in its HTTP/3 DATAGRAM handling. For every previously unseen flow identifier (quarter stream ID) received in a DATAGRAM frame, tokio-quiche creates and retains new, per-flow state. A remote peer can send DATAGRAMs with many distinct identifiers, causing the per-connection flow map and associated channel state to grow without bound.\n\nImpact\n\n\nExploitation can exhaust process memory and cause a denial of service. The vulnerable code is used in both client and server configurations, so either role can be affected by a malicious peer. QUIC DATAGRAM support in tokio-quiche is enabled by default through QuicSettings::enable_dgram; applications can disable it by setting this field to false. The vulnerable HTTP/3 path is reachable only when DATAGRAM support is negotiated with the peer. Core quiche and HTTP/3 deployments without DATAGRAM support are not affected. \n\n\n\n\n\n\nMitigation\n\n\nDisable DATAGRAMs in tokio-quiche’s QuicSettings::enable_dgram.\n\n\n\n\n\n\nRemediation\n\n\nUpgrade to tokio-quiche version 0.23.0 or later. The fixed code creates flow state only for valid DATAGRAM-capable request streams, which are bounded by QUIC’s stream limits. To tolerate packet reordering, servers retain early DATAGRAMs in a bounded, expiring buffer, while clients discard DATAGRAMs for unknown flows.","epss":null,"exploits":[],"kev":null,"metrics":[{"score":8.7,"severity":"high","source":"CNA: cloudflare","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0"}],"modifiedAt":1794318172186,"publishedAt":1794317109558,"references":[{"source":"CNA: cloudflare","tags":[],"url":"https://www.cve.org/CVERecord?id=CVE-2026-12708"},{"source":"CNA: cloudflare","tags":[],"url":"https://github.com/cloudflare/quiche/security/advisories/GHSA-wcm9-jv39-r963"}],"remediation":[],"revision":"2d905955c749df1af1f89f700b0e114b3426e8f4c5c329236b7378ebc8b8b5d0","sources":[{"modifiedAt":1794318172186,"name":"CNA: cloudflare","retrievedAt":1794319857326,"url":"https://www.cve.org/CVERecord?id=CVE-2026-12708"}],"ssvc":null,"status":"published","title":"Unbounded HTTP/3 Datagram flow map growth in tokio-quiche","updatedAt":1794319857326}