CVE-2026-78048

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However, RFC 7541 section 4.1 specifies that the minimum entry size is 33 bytes, because the value may be empty (name >= 1 byte + value == 0 + 32 bytes). For the default 4096-byte table this allocates only 120 slots (4096/34). Eviction in AddHeader is driven by byte usage (_max_size), not by slot count, so a peer can add 121 minimal 33-byte entries (121*33 = 3993 <= 4096) without triggering eviction. The 121st AddHeader then hits CHECK(!_header_queue.full()), which aborts the process.\n\nAffected Scenarios:\nUse a bRPC server that serves HTTP/2 or gRPC requests (e.g. via the h2 protocol) from an untrusted network. The malicious header block is processed during HPACK decoding of incoming requests without authentication.\n\nHow to Fix: \n(Choose one of the following options)\u00a0\n1. Upgrade bRPC to version 1.18.0, which fixes this issue.\n2. Apply this patch:\u00a0https://github.com/apache/brpc/pull/3462\n\nNote:\nThe fix sizes the dynamic table for the 33-byte minimum entry (max_size / (32 + 1)) and ensures at least one ring-buffer slot is kept when max_size is smaller than the minimum entry, so that initialization cannot fail on malloc(0).", "lang": "en", "supportingMedia": [{"type": "text/html", "base64": false, "value": "A reachable-assertion flaw in the HPACK header-compression decoder of the HTTP/2 (h2/gRPC) stack in Apache bRPC (version &lt; 1.18.0) on all platforms allows a remote attacker to crash the server process by sending a crafted sequence of HPACK headers, resulting in a denial of service.<br><br>Root Cause:<br>In src/brpc/details/hpack.cpp, IndexTable::Init sizes the dynamic-table ring buffer as num_headers = max_size / (32 + 2), i.e. it assumes a minimum table entry of 34 bytes (name &gt;= 1 byte + value &gt;= 1 byte + 32 bytes of overhead). However, RFC 7541 section 4.1 specifies that the minimum entry size is 33 bytes, because the value may be empty (name &gt;= 1 byte + value == 0 + 32 bytes). For the default 4096-byte table this allocates only 120 slots (4096/34). Eviction in AddHeader is driven by byte usage (_max_size), not by slot count, so a peer can add 121 minimal 33-byte entries (121*33 = 3993 &lt;= 4096) without triggering eviction. The 121st AddHeader then hits CHECK(!_header_queue.full()), which aborts the process.<br><br>Affected Scenarios:<br>Use a bRPC server that serves HTTP/2 or gRPC requests (e.g. via the h2 protocol) from an untrusted network. The malicious header block is processed during HPACK decoding of incoming requests without authentication.<br><br>How to Fix: <br><span>(Choose one of the following options)&nbsp;</span><br>1. Upgrade bRPC to version 1.18.0, which fixes this issue.<br><span>2. Apply this patch:&nbsp;</span>https://github.com/apache/brpc/pull/3462<br><br>Note:<br>The fix sizes the dynamic table for the 33-byte minimum entry (max_size / (32 + 1)) and ensures at least one ring-buffer slot is kept when max_size is smaller than the minimum entry, so that initialization cannot fail on malloc(0)."}]}], "references": [{"url": "https://lists.apache.org/thread/2pf15ojj0vr7rtx95677kgtl1mx3gdgb", "tags": ["vendor-advisory"]}], "metrics": [{"other": {"type": "Textual description of severity", "content": {"text": "high"}}, "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "credits": [{"lang": "en", "value": "ubeddulla khan", "type": "finder"}], "x_generator": {"engine": "Vulnogram 0.2.0"}}, "adp": [{"metrics": [{"cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}}, {"other": {"type": "ssvc", "content": {"timestamp": "2026-10-30T16:48:59.723519Z", "id": "CVE-2026-78048", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-30T16:49:25.386Z"}}]}}

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However, RFC 7541 section 4.1 specifies that the minimum entry size is 33 bytes, because the value may be empty (name >= 1 byte + value == 0 + 32 bytes). For the default 4096-byte table this allocates only 120 slots (4096/34). Eviction in AddHeader is driven by byte usage (_max_size), not by slot count, so a peer can add 121 minimal 33-byte entries (121*33 = 3993 <= 4096) without triggering eviction. The 121st AddHeader then hits CHECK(!_header_queue.full()), which aborts the process.\n\nAffected Scenarios:\nUse a bRPC server that serves HTTP/2 or gRPC requests (e.g. via the h2 protocol) from an untrusted network. The malicious header block is processed during HPACK decoding of incoming requests without authentication.\n\nHow to Fix: \n(Choose one of the following options)\u00a0\n1. Upgrade bRPC to version 1.18.0, which fixes this issue.\n2. Apply this patch:\u00a0https://github.com/apache/brpc/pull/3462\n\nNote:\nThe fix sizes the dynamic table for the 33-byte minimum entry (max_size / (32 + 1)) and ensures at least one ring-buffer slot is kept when max_size is smaller than the minimum entry, so that initialization cannot fail on malloc(0).", "supportingMedia": [{"type": "text/html", "value": "A reachable-assertion flaw in the HPACK header-compression decoder of the HTTP/2 (h2/gRPC) stack in Apache bRPC (version &lt; 1.18.0) on all platforms allows a remote attacker to crash the server process by sending a crafted sequence of HPACK headers, resulting in a denial of service.<br><br>Root Cause:<br>In src/brpc/details/hpack.cpp, IndexTable::Init sizes the dynamic-table ring buffer as num_headers = max_size / (32 + 2), i.e. it assumes a minimum table entry of 34 bytes (name &gt;= 1 byte + value &gt;= 1 byte + 32 bytes of overhead). 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Apply this patch:&nbsp;</span>https://github.com/apache/brpc/pull/3462<br><br>Note:<br>The fix sizes the dynamic table for the 33-byte minimum entry (max_size / (32 + 1)) and ensures at least one ring-buffer slot is kept when max_size is smaller than the minimum entry, so that initialization cannot fail on malloc(0).", "base64": false}]}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-617", "description": "CWE-617 Reachable Assertion"}]}], "providerMetadata": {"orgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09", "shortName": "apache", "dateUpdated": "2026-10-21T11:51:58.752Z"}}}, "cveMetadata": {"cveId": "CVE-2026-78048", "state": "PUBLISHED", "dateUpdated": "2026-10-30T16:49:25.386Z", "dateReserved": "2026-08-22T04:09:09.653Z", "assignerOrgId": "f0158376-9dc2-43b6-827c-5f631a4d8d09", "datePublished": "2026-10-21T11:51:58.752Z", "assignerShortName": "apache"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"collectionURL": "https://github.com", "defaultStatus": "unaffected", "packageName": "apache/brpc", "packageURL": "pkg:github/apache/brpc", "product": "Apache bRPC", "vendor": "Apache Software Foundation", "versions": [{"lessThan": "1.18.0", "status": "affected", "version": "0", "versionType": "semver"}]}], "source": "security@apache.org"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "A reachable-assertion flaw in the HPACK header-compression decoder of the HTTP/2 (h2/gRPC) stack in Apache bRPC (version < 1.18.0) on all platforms allows a remote attacker to crash the server process by sending a crafted sequence of HPACK headers, resulting in a denial of service.\n\nRoot Cause:\nIn src/brpc/details/hpack.cpp, IndexTable::Init sizes the dynamic-table ring buffer as num_headers = max_size / (32 + 2), i.e. it assumes a minimum table entry of 34 bytes (name >= 1 byte + value >= 1 byte + 32 bytes of overhead). However, RFC 7541 section 4.1 specifies that the minimum entry size is 33 bytes, because the value may be empty (name >= 1 byte + value == 0 + 32 bytes). For the default 4096-byte table this allocates only 120 slots (4096/34). Eviction in AddHeader is driven by byte usage (_max_size), not by slot count, so a peer can add 121 minimal 33-byte entries (121*33 = 3993 <= 4096) without triggering eviction. The 121st AddHeader then hits CHECK(!_header_queue.full()), which aborts the process.\n\nAffected Scenarios:\nUse a bRPC server that serves HTTP/2 or gRPC requests (e.g. via the h2 protocol) from an untrusted network. The malicious header block is processed during HPACK decoding of incoming requests without authentication.\n\nHow to Fix: \n(Choose one of the following options)\u00a0\n1. Upgrade bRPC to version 1.18.0, which fixes this issue.\n2. Apply this patch:\u00a0https://github.com/apache/brpc/pull/3462\n\nNote:\nThe fix sizes the dynamic table for the 33-byte minimum entry (max_size / (32 + 1)) and ensures at least one ring-buffer slot is kept when max_size is smaller than the minimum entry, so that initialization cannot fail on malloc(0)."}, {"lang": "es", "value": "Una vulnerabilidad de aserci\u00f3n alcanzable en el decodificador de compresi\u00f3n de encabezados HPACK de la pila HTTP/2 (h2/gRPC) en Apache bRPC (versi\u00f3n anterior a la 1.18.0) en todas las plataformas permite a un atacante remoto provocar el bloqueo del proceso del servidor enviando una secuencia manipulada de encabezados HPACK, lo que resulta en una denegaci\u00f3n de servicio.\\n\\nCausa ra\u00edz:\\nEn src/brpc/details/hpack.cpp, IndexTable::Init dimensiona el b\u00fafer circular de tabla din\u00e1mica como num_headers = max_size / (32 + 2), es decir, asume una entrada m\u00ednima de tabla de 34?bytes (name >= 1?byte + value mayor o igual a 1?byte + 32?bytes de overhead). Sin embargo, la RFC?7541 secci\u00f3n?4.1 especifica que el tama\u00f1o m\u00ednimo de entrada es de 33?bytes, porque el valor puede estar vac\u00edo (name mayor o igual a 1?byte + value == 0 + 32?bytes). Para la tabla predeterminada de 4096?bytes esto asigna solo 120 ranuras (4096/34). La expulsi\u00f3n en AddHeader se basa en el uso de bytes (_max_size), no en el recuento de ranuras, de modo que un par puede a\u00f1adir 121 entradas m\u00ednimas de 33?bytes (12133 = 3993 menor o igual a 4096) sin activar la expulsi\u00f3n. La 121\u00aa AddHeader entonces alcanza CHECK(!_header_queue.full()), lo que aborta el proceso.\\n\\nEscenarios afectados:\\nUtilice un servidor bRPC que atienda solicitudes HTTP/2 o gRPC (p.?ej., a trav\u00e9s del protocolo h2) desde una red no confiable. El bloque de encabezados malicioso se procesa durante la decodificaci\u00f3n HPACK de las solicitudes entrantes sin autenticaci\u00f3n.\\n\\nC\u00f3mo corregir:\\n1. Actualice bRPC a la versi\u00f3n 1.18.0, que corrige este problema.\\n2. Aplique este parche: https://github.com/apache/brpc/pull/3462\\n\\nNota:\\nLa correcci\u00f3n dimensiona la tabla din\u00e1mica para la entrada m\u00ednima de 33?bytes (max_size / (32 + 1)) y garantiza que al menos una ranura del b\u00fafer circular se mantenga cuando max_size sea menor que la entrada m\u00ednima, de modo que la inicializaci\u00f3n no pueda fallar en malloc(0)."}], "id": "CVE-2026-78048", "lastModified": "2026-10-30T17:17:28.423", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "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:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-78048", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-10-30T16:48:59.723519Z", "version": "2.0.3"}}]}, "published": "2026-10-21T12:17:23.213", "references": [{"source": "security@apache.org", "url": "https://lists.apache.org/thread/2pf15ojj0vr7rtx95677kgtl1mx3gdgb"}], "sourceIdentifier": "security@apache.org", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-617"}], "source": "security@apache.org", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,1.18.0)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "manual", "scores": [{"score": 100.0, "source": "manual"}]}, "original": {"product": "Apache bRPC", "source": "cna", "vendor": "Apache Software Foundation"}, "product": "brpc", "vendor": "apache"}], "created": "2026-10-21T19:30:08.107406+00:00", "updated": "2026-10-30T19:00:17.806715+00:00", "vendors": ["apache", "apache$PRODUCT$brpc"]}