{"id":"CVE-2026-78048","aliases":[],"cve":{"records":[{"id":"CVE-2026-78048","source":"apache","state":"PUBLISHED","reasons":[],"replacements":[],"disputed":false,"unsupportedWhenAssigned":false,"reserved":"2026-08-22T04:09:09.653Z","published":"2026-10-21T11:51:58.752Z","modified":"2026-10-30T16:49:25.386Z"}],"publishers":[{"name":"apache","role":"CNA","organizationId":"f0158376-9dc2-43b6-827c-5f631a4d8d09","modified":"2026-10-21T11:51:58.752Z"},{"name":"CISA-ADP","role":"ADP","organizationId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","modified":"2026-10-30T16:49:25.386Z"}],"references":[{"url":"https://lists.apache.org/thread/2pf15ojj0vr7rtx95677kgtl1mx3gdgb","tags":["vendor-advisory"],"source":"apache"}],"weaknesses":[{"id":"CWE-617","description":"CWE-617 Reachable Assertion","source":"apache"}],"applicability":[],"prioritization":[{"source":"CISA-ADP","type":"SSVC","role":"CISA Coordinator","timestamp":"2026-10-30T16:48:59.723519Z","decisions":[{"name":"Exploitation","value":"none"},{"name":"Automatable","value":"yes"},{"name":"Technical Impact","value":"partial"}]}]},"title":"Apache bRPC: Remote Denial of Service via Out-of-Bounds Dynamic Table Sizing in HPACK Decoder","titleSource":"apache","descriptionSource":"apache","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).","score":7.5,"severity":"high","published":"2026-10-21T11:51:58.752Z","modified":"2026-10-30T16:49:25.386Z","withdrawn":false,"knownExploited":false,"affected":[],"products":[{"vendor":"Apache Software Foundation","name":"Apache bRPC","platforms":[],"versions":[{"version":"0","status":"affected","lessThan":"1.18.0","versionType":"semver"}],"defaultStatus":"unaffected","packageURL":"pkg:github/apache/brpc","cpes":[],"source":"apache","url":"https://www.cve.org/CVERecord?id=CVE-2026-78048"}],"remediation":[],"references":["https://lists.apache.org/thread/2pf15ojj0vr7rtx95677kgtl1mx3gdgb"],"sources":[{"name":"CVE","id":"CVE-2026-78048","modified":"2026-10-30T16:49:25.386Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-78048"}],"assessments":[{"source":"CISA-ADP","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5}],"sourceAffected":[],"observedAt":"2026-10-30T18:16:37.251Z","kev":{"status":"not-listed","checkedAt":"2026-10-31T11:50:31.946Z"},"coverage":[{"source":"NVD","status":"available","checkedAt":"2026-10-30T18:25:31.960Z","attemptedAt":"2026-10-30T18:25:31.960Z"},{"source":"GHSA","status":"available","checkedAt":"2026-10-30T18:25:31.960Z","attemptedAt":"2026-10-30T18:25:31.960Z"},{"source":"EUVD","status":"available","checkedAt":"2026-10-30T18:25:31.960Z","attemptedAt":"2026-10-30T18:25:31.960Z"},{"source":"EPSS","status":"available","checkedAt":"2026-10-30T18:25:31.960Z","attemptedAt":"2026-10-30T18:25:31.960Z"}],"evidence":[{"source":"FIRST EPSS","id":"CVE-2026-78048","url":"https://www.first.org/epss/","probability":0.00242,"percentile":0.15439,"date":"2026-10-30","checkedAt":"2026-10-30T18:25:31.960Z"},{"source":"NVD","id":"CVE-2026-78048","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-78048","modified":"2026-10-30T17:17:28.423","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","checkedAt":"2026-10-30T18:25:31.960Z"},{"source":"GitHub Advisory Database","id":"GHSA-gjf5-p37j-frg4","url":"https://github.com/advisories/GHSA-gjf5-p37j-frg4","modified":"2026-10-21T12:31:22Z","checkedAt":"2026-10-30T18:25:31.960Z"},{"source":"ENISA EUVD","id":"EUVD-2026-107183","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-107183","modified":"Oct 30, 2026, 4:49:25 PM","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","checkedAt":"2026-10-30T18:25:31.960Z"}],"aiSummary":null}