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CVE-2026-84748
Apache bRPC: Builtin services reachable from the public port via protobuf protocols despite ServerOptions.internal_port configuration
Overview
Description

Improper authorization in Apache bRPC (versions < 1.18.0) on all platforms allows remote attackers to access builtin services through the public port. Root Cause: ServerOptions.internal_port is documented to make builtin services (and Tabbed services) reachable only from the internal port, and the HTTP/h2 dispatch path enforced this. However, all protobuf-based protocol dispatch paths (baidu_std, hulu_pbrpc, sofa_pbrpc, and the nshead-based protocols public_pbrpc, nshead_mcpack, nova_pbrpc and ubrpc2pb) computed the security_mode flag but never enforced it between method resolution and method invocation. Since builtin services share the method map with user services, a client able to reach the public port could invoke builtin services such as brpc.vars or hotspots by name over these pb protocols and disclose sensitive runtime information (metrics, flags, profiler data) that the operator intended to expose only via the internal port. Affected Scenarios: Use a bRPC server with ServerOptions.internal_port configured (or with builtin/Tabbed services otherwise expected to be gated by it) while the public port is reachable from an untrusted network and any pb-based protocol is enabled. How to Fix: (Choose one of the following options)  1. Upgrade bRPC to version 1.18.0, which fixes this issue. 2. Apply this patch: https://github.com/apache/brpc/pull/3511

Details
INFO

Published Date :

Oct. 21, 2026, 1:20 p.m.

Last Modified :

Oct. 21, 2026, 1:20 p.m.

Remotely Exploit :

No

Source :

[email protected]
Impact
Affected Products

The following products are affected by CVE-2026-84748 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Apache brpc
: Total Affected Vendor : 1 | Products : 1
Solution
Update Apache bRPC to version 1.18.0 or later to resolve improper authorization.
  • Upgrade Apache bRPC to version 1.18.0.
  • Apply the provided patch if upgrading is not possible.
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-84748.

URL Resource
https://lists.apache.org/thread/2pf15ojj0vr7rtx95677kgtl1mx3gdgb
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-84748 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-84748 weaknesses.

CAPEC-1: Accessing Functionality Not Properly Constrained by ACLs Accessing Functionality Not Properly Constrained by ACLs CAPEC-5: Blue Boxing Blue Boxing CAPEC-13: Subverting Environment Variable Values Subverting Environment Variable Values CAPEC-17: Using Malicious Files Using Malicious Files CAPEC-39: Manipulating Opaque Client-based Data Tokens Manipulating Opaque Client-based Data Tokens CAPEC-45: Buffer Overflow via Symbolic Links Buffer Overflow via Symbolic Links CAPEC-51: Poison Web Service Registry Poison Web Service Registry CAPEC-59: Session Credential Falsification through Prediction Session Credential Falsification through Prediction CAPEC-60: Reusing Session IDs (aka Session Replay) Reusing Session IDs (aka Session Replay) CAPEC-76: Manipulating Web Input to File System Calls Manipulating Web Input to File System Calls CAPEC-77: Manipulating User-Controlled Variables Manipulating User-Controlled Variables CAPEC-87: Forceful Browsing Forceful Browsing CAPEC-104: Cross Zone Scripting Cross Zone Scripting CAPEC-127: Directory Indexing Directory Indexing CAPEC-402: Bypassing ATA Password Security Bypassing ATA Password Security CAPEC-647: Collect Data from Registries Collect Data from Registries CAPEC-668: Key Negotiation of Bluetooth Attack (KNOB) Key Negotiation of Bluetooth Attack (KNOB)

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-84748 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-84748 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Oct. 21, 2026

    Action Type Old Value New Value
    Added Description Improper authorization in Apache bRPC (versions < 1.18.0) on all platforms allows remote attackers to access builtin services through the public port. Root Cause: ServerOptions.internal_port is documented to make builtin services (and Tabbed services) reachable only from the internal port, and the HTTP/h2 dispatch path enforced this. However, all protobuf-based protocol dispatch paths (baidu_std, hulu_pbrpc, sofa_pbrpc, and the nshead-based protocols public_pbrpc, nshead_mcpack, nova_pbrpc and ubrpc2pb) computed the security_mode flag but never enforced it between method resolution and method invocation. Since builtin services share the method map with user services, a client able to reach the public port could invoke builtin services such as brpc.vars or hotspots by name over these pb protocols and disclose sensitive runtime information (metrics, flags, profiler data) that the operator intended to expose only via the internal port. Affected Scenarios: Use a bRPC server with ServerOptions.internal_port configured (or with builtin/Tabbed services otherwise expected to be gated by it) while the public port is reachable from an untrusted network and any pb-based protocol is enabled. How to Fix: (Choose one of the following options)  1. Upgrade bRPC to version 1.18.0, which fixes this issue. 2. Apply this patch: https://github.com/apache/brpc/pull/3511
    Added CWE CWE-285
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/84xxx/CVE-2026-84748.json">CVE-2026-84748</a>
    Added Reference https://lists.apache.org/thread/2pf15ojj0vr7rtx95677kgtl1mx3gdgb
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
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