{"id":"CVE-2026-48854","aliases":["EEF-CVE-2026-48854","EUVD-2026-37012","GHSA-q8gf-9rvj-gmgj"],"status":"published","title":"Unbounded request body accumulation causes memory exhaustion in elixir-grpc/grpc","description":"Allocation of Resources Without Limits or Throttling vulnerability in elixir-grpc grpc allows unauthenticated attackers to exhaust the BEAM's memory and crash the server by streaming a large or slow-trickle unary request body.\n\n'Elixir.GRPC.Server.Adapters.Cowboy.Handler':read_full_body/3 (lib/grpc/server/adapters/cowboy/handler.ex) accumulates every received chunk into a single growing binary with no size cap. Additionally, when the client omits the grpc-timeout header, the per-chunk read timeout resolves to :infinity, allowing a slow-trickle client to keep the connection alive indefinitely while memory grows. A single connection is sufficient to exhaust server memory and crash the node.\n\nThis issue affects grpc: from 0.3.0-alpha.2 before 1.0.0.","severity":{"version":"4.0","score":8.7,"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","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00451,"percentile":0.39418,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-770"],"published":"2026-06-15T21:55:23Z","modified":"2026-10-28T02:31:07Z","fixes":[{"ecosystem":"Hex","package":"grpc","fixed_in":["1.0.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Hex","package":"grpc","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0.3.1"},{"fixed":"1.0.0"}]}]},{"source":"osv","ecosystem":"Hex","package":"grpc","ranges":[{"type":"SEMVER","events":[{"introduced":"0.3.0-alpha.2"},{"fixed":"1.0.0"}]}],"versions":["0.10.0","0.10.1","0.10.2","0.11.0","0.11.1","0.11.2","0.11.3","0.11.4","0.11.5","0.3.0-alpha.2","0.3.1","0.4.0-alpha.1","0.4.0-alpha.2","0.5.0","0.5.0-beta","0.5.0-beta.1","0.6.0","0.7.0","0.8.0","0.8.1","0.9.0","1.0.0-rc.1"]},{"source":"osv","ecosystem":"Hex","package":"grpc","ranges":[{"type":"SEMVER","events":[{"introduced":"0.3.1"},{"fixed":"1.0.0"}]}],"versions":["0.10.0","0.10.1","0.10.2","0.11.0","0.11.1","0.11.2","0.11.3","0.11.4","0.11.5","0.3.1","0.4.0-alpha.1","0.4.0-alpha.2","0.5.0","0.5.0-beta","0.5.0-beta.1","0.6.0","0.7.0","0.8.0","0.8.1","0.9.0","1.0.0-rc.1"]}],"products":[{"vendor":"elixir-grpc","product":"grpc"},{"vendor":"google","product":"grpc"}],"references":[{"url":"https://github.com/elixir-grpc/grpc/security/advisories/GHSA-q8gf-9rvj-gmgj","tags":["vendor-advisory","related","exploit","advisory","web"]},{"url":"https://cna.erlef.org/cves/CVE-2026-48854.html","tags":["related","web"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-48854","tags":["related","web"]},{"url":"https://github.com/elixir-grpc/grpc/commit/d1abe70a6cad6dac4a3f8235d883d7c896989560","tags":["related","fix","web"]},{"url":"https://github.com/elixir-grpc/grpc/commit/49e18c3ec6bb9afe2f712caad3dbab5c56a68a00","tags":["patch","fix","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48854","tags":["advisory"]},{"url":"https://github.com/elixir-grpc/grpc/pull/542","tags":["web"]},{"url":"https://github.com/elixir-grpc/grpc/releases/tag/v1.0.0","tags":["web"]},{"url":"https://github.com/advisories/GHSA-q8gf-9rvj-gmgj"},{"url":"https://github.com","tags":["web"]},{"url":"https://repo.hex.pm","tags":["web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48854.json","tags":["advisory"]},{"url":"https://github.com/elixir-grpc/grpc","tags":["package"]},{"url":"https://hex.pm/packages/grpc","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-48854","title":"Unbounded request body accumulation causes memory exhaustion in elixir-grpc/grpc","description":"Allocation of Resources Without Limits or Throttling vulnerability in elixir-grpc grpc allows unauthenticated attackers to exhaust the BEAM's memory and crash the server by streaming a large or slow-trickle unary request body.\n\n'Elixir.GRPC.Server.Adapters.Cowboy.Handler':read_full_body/3 (lib/grpc/server/adapters/cowboy/handler.ex) accumulates every received chunk into a single growing binary with no size cap. Additionally, when the client omits the grpc-timeout header, the per-chunk read timeout resolves to :infinity, allowing a slow-trickle client to keep the connection alive indefinitely while memory grows. A single connection is sufficient to exhaust server memory and crash the node.\n\nThis issue affects grpc: from 0.3.0-alpha.2 before 1.0.0.","status":"published","published":"2026-06-15T21:55:23.629Z","modified":"2026-09-24T21:09:30.485Z","cvss":[{"version":"4.0","score":8.7,"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","level":"high","assessor":"cna"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T13:50:49.872037Z"}],"euvd":[{"id":"EUVD-2026-37012","description":"Allocation of Resources Without Limits or Throttling vulnerability in elixir-grpc grpc allows unauthenticated attackers to exhaust the BEAM's memory and crash the server by streaming a large or slow-trickle unary request body.\n\n'Elixir.GRPC.Server.Adapters.Cowboy.Handler':read_full_body/3 (lib/grpc/server/adapters/cowboy/handler.ex) accumulates every received chunk into a single growing binary with no size cap. Additionally, when the client omits the grpc-timeout header, the per-chunk read timeout resolves to :infinity, allowing a slow-trickle client to keep the connection alive indefinitely while memory grows. A single connection is sufficient to exhaust server memory and crash the node.\n\nThis issue affects grpc: from 0.3.0-alpha.2 before 1.0.0.","status":"published","published":"2026-06-15T21:55:23Z","modified":"2026-09-24T21:09:30Z","cvss":[{"version":"4.0","score":8.7,"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","level":"high"}],"updated_at":"2026-11-02T17:27:56.296478Z"}],"ghsa":[{"id":"GHSA-q8gf-9rvj-gmgj","title":"gRPC Erlang package has unbounded request body accumulation in `read_full_body/3`","description":"### Summary\n\n`'Elixir.GRPC.Server.Adapters.Cowboy.Handler':read_full_body/3` accumulates every received chunk into a single growing binary with no size cap. When the client omits the `grpc-timeout` header, the read timeout resolves to `:infinity`, allowing a slow-trickle attacker to hold the connection open indefinitely while memory grows. A single unauthenticated connection is sufficient to exhaust BEAM memory and crash the node.\n\n### Details\n\nThe read loop in `lib/grpc/server/adapters/cowboy/handler.ex` calls `:cowboy_req.read_body/2` in a recursive loop, concatenating each chunk: `body \u003c\u003e data`. There is no running-total check and no configurable maximum body size. As the loop drains the receive buffer, cowboy issues fresh HTTP/2 `WINDOW_UPDATE` frames, so the client can keep pushing data indefinitely.\n\nThe `grpc-timeout` header is attacker-supplied and optional. When absent, `timeout_left_opt(nil)` returns `:infinity`, so the per-chunk read also has no deadline. The two missing controls compound: a fast client can blast multi-gigabyte payloads directly into memory; a slow client can trickle data forever.\n\n### PoC\n\n1. Start any `grpc` server exposing a unary RPC (no special configuration required).\n2. Open an HTTP/2 connection and send a POST to any unary RPC path with `Content-Type: application/grpc+proto` — omit the `grpc-timeout` header.\n3. Stream a large body (e.g. 1 GiB) in chunks without sending the final `END_STREAM` flag immediately.\n4. Observe BEAM memory growing proportionally to uploaded data with no server-side cap.\n\n### Impact\n\nAffects `grpc` ≥ 0.3.1. No authentication, no special configuration, and no specific RPC method required, the unbounded read is on the default unary ingress path.\n\n### References\n\n* Introduction commit: https://github.com/elixir-grpc/grpc/commit/d1abe70a6cad6dac4a3f8235d883d7c896989560\n* Patch commit: https://github.com/elixir-grpc/grpc/commit/49e18c3ec6bb9afe2f712caad3dbab5c56a68a00","status":"published","published":"2026-08-25T18:12:05Z","modified":"2026-08-25T18:12:07Z","cvss":[{"version":"4.0","score":8.7,"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","level":"high"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T14:41:05.994358Z"}],"nvd":[{"id":"CVE-2026-48854","description":"Allocation of Resources Without Limits or Throttling vulnerability in elixir-grpc grpc allows unauthenticated attackers to exhaust the BEAM's memory and crash the server by streaming a large or slow-trickle unary request body.\n\n'Elixir.GRPC.Server.Adapters.Cowboy.Handler':read_full_body/3 (lib/grpc/server/adapters/cowboy/handler.ex) accumulates every received chunk into a single growing binary with no size cap. Additionally, when the client omits the grpc-timeout header, the per-chunk read timeout resolves to :infinity, allowing a slow-trickle client to keep the connection alive indefinitely while memory grows. A single connection is sufficient to exhaust server memory and crash the node.\n\nThis issue affects grpc: from 0.3.0-alpha.2 before 1.0.0.","status":"published","published":"2026-06-15T23:16:45.813Z","modified":"2026-10-25T23:10:00.167Z","cvss":[{"version":"4.0","score":8.7,"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high","assessor":"secondary"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T14:12:24.19758Z"}],"osv":[{"id":"CVE-2026-48854","title":"Unbounded request body accumulation causes memory exhaustion in elixir-grpc/grpc","description":"Allocation of Resources Without Limits or Throttling vulnerability in elixir-grpc grpc allows unauthenticated attackers to exhaust the BEAM's memory and crash the server by streaming a large or slow-trickle unary request body.\n\n'Elixir.GRPC.Server.Adapters.Cowboy.Handler':read_full_body/3 (lib/grpc/server/adapters/cowboy/handler.ex) accumulates every received chunk into a single growing binary with no size cap. Additionally, when the client omits the grpc-timeout header, the per-chunk read timeout resolves to :infinity, allowing a slow-trickle client to keep the connection alive indefinitely while memory grows. A single connection is sufficient to exhaust server memory and crash the node.\n\nThis issue affects grpc: from 0.3.0-alpha.2 before 1.0.0.","status":"published","published":"2026-06-15T21:55:23.629Z","modified":"2026-10-28T02:31:07.18017886Z","cvss":[{"version":"4.0","score":8.7,"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","level":"high"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T15:45:06.701612Z"},{"id":"EEF-CVE-2026-48854","title":"Unbounded request body accumulation causes memory exhaustion in elixir-grpc/grpc","description":"## Summary\n\nAllocation of Resources Without Limits or Throttling vulnerability in elixir-grpc grpc allows unauthenticated attackers to exhaust the BEAM's memory and crash the server by streaming a large or slow-trickle unary request body.\n\n`'Elixir.GRPC.Server.Adapters.Cowboy.Handler':read_full_body/3` (`lib/grpc/server/adapters/cowboy/handler.ex`) accumulates every received chunk into a single growing binary with no size cap. Additionally, when the client omits the `grpc-timeout` header, the per-chunk read timeout resolves to `:infinity`, allowing a slow-trickle client to keep the connection alive indefinitely while memory grows. A single connection is sufficient to exhaust server memory and crash the node.\n\nThis issue affects grpc: from 0.3.0-alpha.2 before 1.0.0.","status":"published","published":"2026-06-15T21:55:23.629Z","modified":"2026-09-24T21:15:02.933406115Z","cvss":[{"version":"4.0","score":8.7,"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","level":"high"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T15:46:33.520522Z"},{"id":"GHSA-q8gf-9rvj-gmgj","title":"gRPC Erlang package has unbounded request body accumulation in `read_full_body/3`","description":"### Summary\n\n`'Elixir.GRPC.Server.Adapters.Cowboy.Handler':read_full_body/3` accumulates every received chunk into a single growing binary with no size cap. When the client omits the `grpc-timeout` header, the read timeout resolves to `:infinity`, allowing a slow-trickle attacker to hold the connection open indefinitely while memory grows. A single unauthenticated connection is sufficient to exhaust BEAM memory and crash the node.\n\n### Details\n\nThe read loop in `lib/grpc/server/adapters/cowboy/handler.ex` calls `:cowboy_req.read_body/2` in a recursive loop, concatenating each chunk: `body \u003c\u003e data`. There is no running-total check and no configurable maximum body size. As the loop drains the receive buffer, cowboy issues fresh HTTP/2 `WINDOW_UPDATE` frames, so the client can keep pushing data indefinitely.\n\nThe `grpc-timeout` header is attacker-supplied and optional. When absent, `timeout_left_opt(nil)` returns `:infinity`, so the per-chunk read also has no deadline. The two missing controls compound: a fast client can blast multi-gigabyte payloads directly into memory; a slow client can trickle data forever.\n\n### PoC\n\n1. Start any `grpc` server exposing a unary RPC (no special configuration required).\n2. Open an HTTP/2 connection and send a POST to any unary RPC path with `Content-Type: application/grpc+proto` — omit the `grpc-timeout` header.\n3. Stream a large body (e.g. 1 GiB) in chunks without sending the final `END_STREAM` flag immediately.\n4. Observe BEAM memory growing proportionally to uploaded data with no server-side cap.\n\n### Impact\n\nAffects `grpc` ≥ 0.3.1. No authentication, no special configuration, and no specific RPC method required, the unbounded read is on the default unary ingress path.\n\n### References\n\n* Introduction commit: https://github.com/elixir-grpc/grpc/commit/d1abe70a6cad6dac4a3f8235d883d7c896989560\n* Patch commit: https://github.com/elixir-grpc/grpc/commit/49e18c3ec6bb9afe2f712caad3dbab5c56a68a00","status":"published","published":"2026-08-25T18:12:05Z","modified":"2026-08-26T00:38:22.365753202Z","cvss":[{"version":"4.0","score":8.7,"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","level":"high"}],"cwes":["CWE-770"],"updated_at":"2026-11-02T15:46:54.40888Z"}]}}