{"id":"CVE-2026-74755","aliases":[],"cve":{"records":[{"id":"CVE-2026-74755","source":"apache","state":"PUBLISHED","reasons":[],"replacements":[],"disputed":false,"unsupportedWhenAssigned":false,"reserved":"2026-08-15T06:31:05.828Z","published":"2026-10-21T11:45:25.658Z","modified":"2026-10-30T17:56:42.592Z"}],"publishers":[{"name":"apache","role":"CNA","organizationId":"f0158376-9dc2-43b6-827c-5f631a4d8d09","modified":"2026-10-21T11:45:25.658Z"},{"name":"CISA-ADP","role":"ADP","organizationId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","modified":"2026-10-30T17:56:42.592Z"}],"references":[{"url":"https://lists.apache.org/thread/2pf15ojj0vr7rtx95677kgtl1mx3gdgb","tags":["vendor-advisory"],"source":"apache"}],"weaknesses":[{"id":"CWE-191","description":"CWE-191 Integer Underflow (Wrap or Wraparound)","source":"apache"}],"applicability":[],"prioritization":[{"source":"CISA-ADP","type":"SSVC","role":"CISA Coordinator","timestamp":"2026-10-30T17:56:37.339174Z","decisions":[{"name":"Exploitation","value":"none"},{"name":"Automatable","value":"yes"},{"name":"Technical Impact","value":"partial"}]}]},"title":"Apache bRPC: Integer Underflow in mcpack2pb Parser Leading to Denial of Service","titleSource":"apache","descriptionSource":"apache","description":"An integer underflow in the mcpack2pb component of Apache bRPC (version < 1.18.0) on all platforms allows remote attackers to crash a bRPC server by sending a request containing a string field with a zero value_size. The UnparsedValue::as_string() function computes `_size - 1` without validating `_size`; when value_size is 0 the expression underflows to SIZE_MAX, resize() throws std::length_error, and because the exception is not caught on the request parsing path the process aborts (SIGABRT).\n\nRoot Cause:\nIn src/mcpack2pb/parser.cpp, UnparsedValue::as_string() resizes the output string to `_size - 1`, where `_size` is the value_size of a string field taken directly from the network data. A value_size of 0 underflows the unsigned size_t, and the subsequent resize() throws an exception that is not caught.\n\nAffected Scenarios:\nbRPC servers that accept nshead frames wired to the ubrpc mcpack2 adaptor (for example the NsheadService + UbrpcMcpack2Adaptor deployment pattern) can be crashed by a single unauthenticated request. Stock open-source bRPC registers the ubrpc/nshead_mcpack protocols as client-only, so default server configurations are not affected.\n\nHow to Fix:\n1. Upgrade bRPC to a version that includes this fix.\n2. Apply the patch in PR  https://github.com/apache/brpc/pull/3450","score":7.5,"severity":"high","published":"2026-10-21T11:45:25.658Z","modified":"2026-10-30T17:56:42.592Z","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-2026-74755"}],"remediation":[],"references":["https://lists.apache.org/thread/2pf15ojj0vr7rtx95677kgtl1mx3gdgb"],"sources":[{"name":"CVE","id":"CVE-2026-74755","modified":"2026-10-30T17:56:42.592Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-74755"}],"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":"2026-10-30T18:27:57.706Z","kev":{"status":"not-listed","checkedAt":"2026-10-31T12:10:30.804Z"},"coverage":[{"source":"NVD","status":"available","checkedAt":"2026-10-30T18:35:37.195Z","attemptedAt":"2026-10-30T18:35:37.195Z"},{"source":"GHSA","status":"available","checkedAt":"2026-10-30T18:35:36.694Z","attemptedAt":"2026-10-30T18:35:36.694Z"},{"source":"EUVD","status":"available","checkedAt":"2026-10-30T18:35:37.160Z","attemptedAt":"2026-10-30T18:35:37.160Z"},{"source":"EPSS","status":"available","checkedAt":"2026-10-30T18:35:36.687Z","attemptedAt":"2026-10-30T18:35:36.687Z"}],"evidence":[{"source":"FIRST EPSS","id":"CVE-2026-74755","url":"https://www.first.org/epss/","probability":0.00202,"percentile":0.10168,"date":"2026-10-30","checkedAt":"2026-10-30T18:35:36.687Z"},{"source":"GitHub Advisory Database","id":"GHSA-9644-97m2-4fc3","url":"https://github.com/advisories/GHSA-9644-97m2-4fc3","modified":"2026-10-30T18:33:23Z","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","checkedAt":"2026-10-30T18:35:36.694Z"},{"source":"ENISA EUVD","id":"EUVD-2026-107180","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-107180","modified":"Oct 21, 2026, 11:45:25 AM","checkedAt":"2026-10-30T18:35:37.160Z"},{"source":"NVD","id":"CVE-2026-74755","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74755","modified":"2026-10-30T18:18:12.603","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","checkedAt":"2026-10-30T18:35:37.195Z"}],"aiSummary":null}