{"api_version":"1","generated_at":"2026-10-22T01:48:59+00:00","cve":"CVE-2026-78048","urls":{"html":"https://cve.report/CVE-2026-78048","api":"https://cve.report/api/cve/CVE-2026-78048.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-78048","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-78048"},"summary":{"title":"Apache bRPC: Remote Denial of Service via Out-of-Bounds Dynamic Table Sizing in HPACK Decoder","description":"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) \n1. Upgrade bRPC to version 1.18.0, which fixes this issue.\n2. Apply this patch: https://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).","state":"PUBLISHED","assigner":"apache","published_at":"2026-10-21 12:17:23","updated_at":"2026-10-21 12:17:23"},"problem_types":["CWE-617","CWE-617 CWE-617 Reachable Assertion"],"metrics":[],"references":[{"url":"https://lists.apache.org/thread/2pf15ojj0vr7rtx95677kgtl1mx3gdgb","name":"https://lists.apache.org/thread/2pf15ojj0vr7rtx95677kgtl1mx3gdgb","refsource":"security@apache.org","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-78048","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-78048","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Apache Software Foundation","product":"Apache bRPC","version":"affected 1.18.0 semver","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[{"source":"CNA","value":"ubeddulla khan","lang":"en"}],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"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"}]}],"credits":[{"lang":"en","type":"finder","value":"ubeddulla khan"}],"descriptions":[{"lang":"en","supportingMedia":[{"base64":false,"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). 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)."}],"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) \n1. Upgrade bRPC to version 1.18.0, which fixes this issue.\n2. Apply this patch: https://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)."}],"metrics":[{"other":{"content":{"text":"high"},"type":"Textual description of severity"},"scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-617","description":"CWE-617 Reachable Assertion","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-10-21T11:51:58.752Z","orgId":"f0158376-9dc2-43b6-827c-5f631a4d8d09","shortName":"apache"},"references":[{"tags":["vendor-advisory"],"url":"https://lists.apache.org/thread/2pf15ojj0vr7rtx95677kgtl1mx3gdgb"}],"source":{"discovery":"EXTERNAL"},"title":"Apache bRPC: Remote Denial of Service via Out-of-Bounds Dynamic Table Sizing in HPACK Decoder","x_generator":{"engine":"Vulnogram 0.2.0"}}},"cveMetadata":{"assignerOrgId":"f0158376-9dc2-43b6-827c-5f631a4d8d09","assignerShortName":"apache","cveId":"CVE-2026-78048","datePublished":"2026-10-21T11:51:58.752Z","dateReserved":"2026-08-22T04:09:09.653Z","dateUpdated":"2026-10-21T11:51:58.752Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-21 12:17:23","lastModifiedDate":"2026-10-21 12:17:23","problem_types":["CWE-617","CWE-617 CWE-617 Reachable Assertion"],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"78048","Ordinal":"1","Title":"Apache bRPC: Remote Denial of Service via Out-of-Bounds Dynamic ","CVE":"CVE-2026-78048","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"78048","Ordinal":"1","NoteData":"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) \n1. Upgrade bRPC to version 1.18.0, which fixes this issue.\n2. Apply this patch: https://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).","Type":"Description","Title":"Apache bRPC: Remote Denial of Service via Out-of-Bounds Dynamic "}]}}}