Vulnerability-Lookup

GHSA-9644-97M2-4FC3

Vulnerability from github – Published: 2026-10-21 12:31 – Updated: 2026-10-21 12:31

Details

Root Cause: In 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.

Affected Scenarios: bRPC 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.

How to Fix: 1. Upgrade bRPC to a version that includes this fix. 2. Apply the patch in PR https://github.com/apache/brpc/pull/3450

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{
  "affected": [],
  "aliases": [
    "CVE-2026-74755"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-191"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-21T12:17:22Z",
    "severity": null
  },
  "details": "An integer underflow in the mcpack2pb component of Apache bRPC (version \u003c 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\u00a0 https://github.com/apache/brpc/pull/3450",
  "id": "GHSA-9644-97m2-4fc3",
  "modified": "2026-10-21T12:31:11Z",
  "published": "2026-10-21T12:31:11Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74755"
    },
    {
      "type": "WEB",
      "url": "https://lists.apache.org/thread/2pf15ojj0vr7rtx95677kgtl1mx3gdgb"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-74755 (GCVE-0-2026-74755)

Vulnerability from cvelistv5 – Published: 2026-10-21 11:45 – Updated: 2026-10-21 11:45

Title

Apache bRPC: Integer Underflow in mcpack2pb Parser Leading to Denial of Service

Summary

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). Root Cause: In 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. Affected Scenarios: bRPC 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. How to Fix: 1. Upgrade bRPC to a version that includes this fix. 2. Apply the patch in PR https://github.com/apache/brpc/pull/3450

Severity

No CVSS data available.

CWE

CWE-191 - Integer Underflow (Wrap or Wraparound)

Assigner

apache CNA under the mitre root

CNA scorecard B 76/100 over 1056 records in the last 180 days details

References

1 reference

URL	Tags
https://lists.apache.org/thread/2pf15ojj0vr7rtx95…	vendor-advisory

Impacted products

1 product

Vendor	Product	Version
Apache Software Foundation	Apache bRPC	Affected: 0 , < 1.18.0 (semver)

Credits

Feng Zhijie (Independent security researcher)

Show details on NVD website

JSON

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Sightings

Author	Source	Type	Date	Other

Nomenclature

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Confirmed: The vulnerability has been validated from an analyst's perspective.
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Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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