{"id":"CVE-2026-48862","state":"PUBLISHED","title":"Unbounded conn.streams growth in Mint HTTP/2 client via unenforced PUSH_PROMISE concurrency","description":"Allocation of Resources Without Limits or Throttling vulnerability in elixir-mint Mint allows attacker-controlled HTTP/2 servers to exhaust memory in a Mint client via PUSH_PROMISE flooding.\n\nIn lib/mint/http2.ex, Mint.HTTP2.decode_push_promise_headers_and_add_response/5 inserts a :reserved_remote entry into conn.streams for every promised stream ID. The neighbouring Mint.HTTP2.assert_valid_promised_stream_id/2 only verifies that the promised ID is even and not already present; client_settings.max_concurrent_streams is not consulted at promise time. The concurrency cap is only checked when the response HEADERS for the promised stream arrive, so a server that emits PUSH_PROMISE frames and withholds the matching HEADERS never trips that check.\n\nHTTP/2 server push is accepted by default (client_settings.enable_push defaults to true). A single long-lived HTTP/2 connection to a hostile server lets that server pin one conn.streams entry per PUSH_PROMISE frame it sends, with no upper bound, until the client process runs out of memory.\n\nThis issue affects mint: from 0.2.0 before 1.9.0.","publishedAt":"2026-06-02T14:15:10.591Z","updatedAt":"2026-06-02T19:14:09.683Z","severity":{"score":8.2,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","source":"EEF"},"assigner":"EEF","products":["elixir-mint mint"],"affected":[{"vendor":"elixir-mint","product":"mint","packageName":"mint","packageURL":"pkg:hex/mint","defaultStatus":"unaffected","versions":[{"version":"0.2.0","status":"affected","lessThan":"1.9.0","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:elixir-mint:mint:*:*:*:*:*:*:*:*"],"modules":["'Elixir.Mint.HTTP2'"],"programFiles":["lib/mint/http2.ex"],"programRoutines":[{"name":"'Elixir.Mint.HTTP2':handle_push_promise/3"},{"name":"'Elixir.Mint.HTTP2':decode_push_promise_headers_and_add_response/5"}],"repo":"https://github.com/elixir-mint/mint"},{"vendor":"elixir-mint","product":"mint","packageName":"elixir-mint/mint","packageURL":"pkg:github/elixir-mint/mint","defaultStatus":"unaffected","versions":[{"version":"65c6394d05a1b8aa4a7461708c3aa173e8d7a5cf","status":"affected","lessThan":"70b97b6a5209fb288b0e04d8e657dda26c59de67","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:elixir-mint:mint:*:*:*:*:*:*:*:*"],"modules":["'Elixir.Mint.HTTP2'"],"programFiles":["lib/mint/http2.ex"],"programRoutines":[{"name":"'Elixir.Mint.HTTP2':handle_push_promise/3"},{"name":"'Elixir.Mint.HTTP2':decode_push_promise_headers_and_add_response/5"}],"repo":"https://github.com/elixir-mint/mint.git"}],"references":["https://github.com/elixir-mint/mint/security/advisories/GHSA-g586-ccqf-7x4r","https://cna.erlef.org/cves/CVE-2026-48862.html","https://osv.dev/vulnerability/EEF-CVE-2026-48862","https://github.com/elixir-mint/mint/commit/70b97b6a5209fb288b0e04d8e657dda26c59de67"],"weaknesses":["CWE-770"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/48xxx/CVE-2026-48862.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-48862","state":"PUBLISHED","datePublished":"2026-06-02T14:15:10.591Z","dateUpdated":"2026-06-02T19:14:09.683Z","assignerShortName":"EEF","assignerOrgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateReserved":"2026-05-25T20:44:10.697Z"},"containers":{"cna":{"title":"Unbounded conn.streams growth in Mint HTTP/2 client via unenforced PUSH_PROMISE concurrency","descriptions":[{"lang":"en","value":"Allocation of Resources Without Limits or Throttling vulnerability in elixir-mint Mint allows attacker-controlled HTTP/2 servers to exhaust memory in a Mint client via PUSH_PROMISE flooding.\n\nIn lib/mint/http2.ex, Mint.HTTP2.decode_push_promise_headers_and_add_response/5 inserts a :reserved_remote entry into conn.streams for every promised stream ID. The neighbouring Mint.HTTP2.assert_valid_promised_stream_id/2 only verifies that the promised ID is even and not already present; client_settings.max_concurrent_streams is not consulted at promise time. The concurrency cap is only checked when the response HEADERS for the promised stream arrive, so a server that emits PUSH_PROMISE frames and withholds the matching HEADERS never trips that check.\n\nHTTP/2 server push is accepted by default (client_settings.enable_push defaults to true). A single long-lived HTTP/2 connection to a hostile server lets that server pin one conn.streams entry per PUSH_PROMISE frame it sends, with no upper bound, until the client process runs out of memory.\n\nThis issue affects mint: from 0.2.0 before 1.9.0."}],"affected":[{"vendor":"elixir-mint","product":"mint","packageName":"mint","packageURL":"pkg:hex/mint","defaultStatus":"unaffected","versions":[{"version":"0.2.0","status":"affected","lessThan":"1.9.0","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:elixir-mint:mint:*:*:*:*:*:*:*:*"],"modules":["'Elixir.Mint.HTTP2'"],"programFiles":["lib/mint/http2.ex"],"programRoutines":[{"name":"'Elixir.Mint.HTTP2':handle_push_promise/3"},{"name":"'Elixir.Mint.HTTP2':decode_push_promise_headers_and_add_response/5"}],"repo":"https://github.com/elixir-mint/mint"},{"vendor":"elixir-mint","product":"mint","packageName":"elixir-mint/mint","packageURL":"pkg:github/elixir-mint/mint","defaultStatus":"unaffected","versions":[{"version":"65c6394d05a1b8aa4a7461708c3aa173e8d7a5cf","status":"affected","lessThan":"70b97b6a5209fb288b0e04d8e657dda26c59de67","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:elixir-mint:mint:*:*:*:*:*:*:*:*"],"modules":["'Elixir.Mint.HTTP2'"],"programFiles":["lib/mint/http2.ex"],"programRoutines":[{"name":"'Elixir.Mint.HTTP2':handle_push_promise/3"},{"name":"'Elixir.Mint.HTTP2':decode_push_promise_headers_and_add_response/5"}],"repo":"https://github.com/elixir-mint/mint.git"}],"references":[{"url":"https://github.com/elixir-mint/mint/security/advisories/GHSA-g586-ccqf-7x4r","tags":["vendor-advisory","related"]},{"url":"https://cna.erlef.org/cves/CVE-2026-48862.html","tags":["related"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-48862","tags":["related"]},{"url":"https://github.com/elixir-mint/mint/commit/70b97b6a5209fb288b0e04d8e657dda26c59de67","tags":["patch"]}],"metrics":[{"cvssV4_0":{"attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":8.2,"baseSeverity":"HIGH","privilegesRequired":"NONE","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-770","description":"CWE-770 Allocation of Resources Without Limits or Throttling","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"EEF","orgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateUpdated":"2026-06-02T19:14:09.683Z"},"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:a:elixir-mint:mint:*:*:*:*:*:*:*:*","versionEndExcluding":"1.9.0","versionStartIncluding":"0.2.0","vulnerable":true}],"negate":false,"operator":"OR"}],"operator":"AND"}],"credits":[{"lang":"en","type":"finder","value":"Peter Ullrich"},{"lang":"en","type":"remediation developer","value":"Eric Meadows-Jönsson"},{"lang":"en","type":"analyst","value":"Jonatan Männchen / EEF"}],"impacts":[{"capecId":"CAPEC-130","descriptions":[{"lang":"en","value":"CAPEC-130 Excessive Allocation"}]}],"source":{"discovery":"EXTERNAL"},"workarounds":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"<p>Disable HTTP/2 server push on connections to untrusted servers by passing <tt>client_settings: [enable_push: false]</tt> to <tt>'Elixir.Mint.HTTP':connect/4</tt>. This makes Mint reject any inbound <tt>PUSH_PROMISE</tt> frame with a <tt>PROTOCOL_ERROR</tt> before the vulnerable code path is reached.</p>"}],"value":"Disable HTTP/2 server push on connections to untrusted servers by passing client_settings: [enable_push: false] to Mint.HTTP.connect/4. This makes Mint reject any inbound PUSH_PROMISE frame with a PROTOCOL_ERROR before the vulnerable code path is reached."}],"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/elixir-mint/mint/security/advisories/GHSA-g586-ccqf-7x4r","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-02T18:11:00.524487Z","id":"CVE-2026-48862","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-06-02T18:11:05.599Z"}}]}}}