CVE-2026-74836

{"id": "CVE-2026-74836", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-74836", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-08-21T19:54:42.335290Z"}}], "cvssMetricV40": [{"type": "Secondary", "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 8.7, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "HIGH", "valueDensity": "NOT_DEFINED", "vectorString": "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", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "affected": [{"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "affectedData": [{"cpes": ["cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*"], "repo": "https://github.com/mtrudel/bandit", "vendor": "mtrudel", "modules": ["'Elixir.Bandit.HTTP2.Connection'", "'Elixir.Bandit.HTTP2.Stream'"], "product": "bandit", "versions": [{"status": "affected", "version": "0.3.4", "lessThan": "1.12.5", "versionType": "semver"}], "packageURL": "pkg:hex/bandit", "packageName": "bandit", "programFiles": ["lib/bandit/http2/connection.ex", "lib/bandit/http2/stream.ex"], "collectionURL": "https://repo.hex.pm", "defaultStatus": "unaffected", "programRoutines": [{"name": "'Elixir.Bandit.HTTP2.Connection':finish_data/5"}, {"name": "'Elixir.Bandit.HTTP2.Connection':handle_frame/3"}, {"name": "'Elixir.Bandit.HTTP2.Stream':send_data/3"}]}, {"cpes": ["cpe:2.3:a:mtrudel:bandit:*:*:*:*:*:*:*:*"], "repo": "https://github.com/mtrudel/bandit", "vendor": "mtrudel", "modules": ["'Elixir.Bandit.HTTP2.Connection'", "'Elixir.Bandit.HTTP2.Stream'"], "product": "bandit", "versions": [{"status": "affected", "version": "6feadb31189d18b7dcda6c663112cd3bbaf63a46", "lessThan": "f6914aad14bb1365dd6f306aa592cfb0819bed3e", "versionType": "git"}], "packageURL": "pkg:github/mtrudel/bandit", "packageName": "mtrudel/bandit", "programFiles": ["lib/bandit/http2/connection.ex", "lib/bandit/http2/stream.ex"], "collectionURL": "https://github.com", "defaultStatus": "unaffected", "programRoutines": [{"name": "'Elixir.Bandit.HTTP2.Connection':finish_data/5"}, {"name": "'Elixir.Bandit.HTTP2.Connection':handle_frame/3"}, {"name": "'Elixir.Bandit.HTTP2.Stream':send_data/3"}]}]}], "published": "2026-08-20T21:17:09.407", "references": [{"url": "https://cna.erlef.org/cves/CVE-2026-74836.html", "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}, {"url": "https://github.com/mtrudel/bandit/commit/f6914aad14bb1365dd6f306aa592cfb0819bed3e", "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}, {"url": "https://github.com/mtrudel/bandit/security/advisories/GHSA-xj8g-532w-jv94", "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}, {"url": "https://osv.dev/vulnerability/EEF-CVE-2026-74836", "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}, {"url": "https://github.com/mtrudel/bandit/security/advisories/GHSA-xj8g-532w-jv94", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Awaiting Analysis", "weaknesses": [{"type": "Secondary", "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "description": [{"lang": "en", "value": "CWE-770"}]}], "descriptions": [{"lang": "en", "value": "Allocation of Resources Without Limits or Throttling vulnerability in mtrudel bandit allows an unauthenticated remote attacker to pin an unbounded number of HTTP/2 stream processes indefinitely via connection-level flow control. When a stream's response body outruns the HTTP/2 connection-level send window (default 65,535 bytes, shared across all streams on the connection), Bandit.HTTP2.Connection queues the remaining bytes and a reply closure in pending_sends and the stream process blocks forever inside a synchronous call to the connection process. Nothing bounds that wait and nothing purges the queue: a client RST_STREAM for the blocked stream is delivered to its mailbox but never read while it is stuck inside the call, so cancelling frees nothing, and periodic PING frames keep the transport-level read timeout from ever firing. The equivalent block on the stream-level send window is already bounded at 15 seconds; the connection-level path had no such bound.\n\nEach stalled stream pins its process, Plug state, and any resource the Plug holds across the blocked write, such as a pooled upstream connection in a reverse-proxy Plug. The attacker chooses any endpoint whose response exceeds the connection window (common for most non-trivial payloads), grants a generous stream-level window so only the connection window limits it, and keeps the connection alive with periodic PINGs; the primitive is repeatable across streams and connections at the cost of one idle socket each.\n\nThis issue affects bandit: from 0.3.4 before 1.12.5."}, {"lang": "es", "value": "Vulnerabilidad de asignaci\u00f3n de recursos sin l\u00edmites ni limitaci\u00f3n (throttling) en mtrudel bandit permite a un atacante remoto no autenticado fijar un n\u00famero ilimitado de procesos de flujo HTTP/2 indefinidamente a trav\u00e9s del control de flujo a nivel de conexi\u00f3n. Cuando el cuerpo de respuesta de un flujo excede la ventana de env\u00edo a nivel de conexi\u00f3n HTTP/2 (predeterminado 65.535 bytes, compartido entre todos los flujos en la conexi\u00f3n), Bandit.HTTP2.Connection encola los bytes restantes y un cierre de respuesta en pending_sends y el proceso de flujo se bloquea para siempre dentro de una llamada s\u00edncrona al proceso de conexi\u00f3n. Nada limita esa espera y nada purga la cola: un RST_STREAM del cliente para el flujo bloqueado se entrega a su buz\u00f3n pero nunca se lee mientras est\u00e1 atascado dentro de la llamada, por lo que la cancelaci\u00f3n no libera nada, y los frames PING peri\u00f3dicos evitan que el tiempo de espera de lectura a nivel de transporte se active. El bloqueo equivalente en la ventana de env\u00edo a nivel de flujo ya est\u00e1 limitado a 15 segundos; la ruta a nivel de conexi\u00f3n no ten\u00eda tal l\u00edmite.\n\nCada flujo estancado fija su proceso, estado de Plug, y cualquier recurso que el Plug mantenga durante la escritura bloqueada, como una conexi\u00f3n upstream agrupada en un Plug de proxy inverso. El atacante elige cualquier endpoint cuya respuesta exceda la ventana de conexi\u00f3n (com\u00fan para la mayor\u00eda de las cargas \u00fatiles no triviales), otorga una ventana generosa a nivel de flujo para que solo la ventana de conexi\u00f3n lo limite, y mantiene la conexi\u00f3n viva con PINGs peri\u00f3dicos; la primitiva es repetible a trav\u00e9s de flujos y conexiones a costa de un socket inactivo cada una.\n\nEste problema afecta a bandit: desde 0.3.4 antes de 1.12.5."}], "lastModified": "2026-10-18T20:10:00.110", "sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}