CVE-2026-84747
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk40th percentile - higher than 40% of all known CVEs
Summary
A vulnerability in Apache bRPC (versions < 1.18.0) stems from an interpretation conflict in HTTP path handling between bRPC and a front proxy. The FindMethodPropertyByURI() function skips empty path segments (consecutive slashes), so paths like //flags are dispatched as /flags, even though RFC 3986 treats them as distinct. Additionally, HTTP/2 does not validate the :path pseudo-header, allowing bypass of proxy ACL rules and access to internal services.
Risk Assessment
An attacker can bypass front proxy access control and reach restricted built-in bRPC services such as /flags, potentially leading to unauthorized configuration changes or information disclosure.
Recommendation
Upgrade Apache bRPC to version 1.18.0 or apply the patch from PR #3512. Do not enable the -http_allow_empty_path_segments flag on servers exposed to untrusted traffic.
Other vulnerabilities in Apache bRPC
See all- CVE-2026-86249Critical
On a brpc::Server that sets both ServerOptions.auth and ServerOptions.internal_port, the HTTP built-in service exemption on internal_port can be abused to bypass authentication entirely. Verification runs only for the first message of a connection and the result latches the connection, so a request such as GET /status to internal_port authenticates the whole connection.
- CVE-2026-78334Critical
Missing authentication in the streaming RPC path of Apache bRPC (version < 1.18.0) allows a remote attacker to bypass server authentication and inject or deliver streaming frames when a server is configured with an Authenticator. Streaming frames never pass through the authentication hook, and streams can be impersonated by another socket carrying the same id.
- CVE-2026-56388Critical
The Redis server command parser in Apache bRPC accepts an empty RESP array as a command header. A remote unauthenticated attacker can send an empty array header followed by a bulk string, causing an out-of-bounds write in the parser and crashing the process.
- CVE-2026-48830Critical
Improper authentication in Apache bRPC through 1.17.0 allows a remote unauthenticated attacker to bypass authentication for protected builtin HTTP endpoints by first sending a builtin HTTP request on the same HTTP/1.1 keep-alive connection. When ServerOptions.auth is enabled and builtin HTTP services are publicly exposed, the first builtin request may mark the connection as authenticated for later requests.
- CVE-2025-60021Critical
Remote command injection vulnerability in heap profiler builtin service in Apache bRPC (all versions < 1.15.0) on all platforms allows attacker to inject remote command. Root Cause: The bRPC heap profiler built-in service (/pprof/heap) does not validate the user-provided extra_options parameter and executes it as a command-line argument. Attackers can execute remote commands using the extra_options parameter. Affected scenarios: Use the built-in bRPC heap profiler service to perform jemalloc memory profiling. How to Fix: we provide two methods, you can choose one of them: 1. Upgrade bRPC to version 1.15.0. 2. Apply this patch ( https://github.com/apache/brpc/pull/3101 ) manually.
- CVE-2023-31039Critical
Apache bRPC < 1.5.0 on all platforms allows attackers to execute arbitrary code via the ServerOptions::pid_file parameter. An attacker who can influence this parameter when starting the bRPC server can execute arbitrary code with the permissions of the bRPC process.
- CVE-2026-90484Medium
The MySQL client response parser in Apache bRPC dereferences a null pointer when the server peer sends a zero-payload-length response packet. A packet with declared zero payload length passes the frame-length check, after which the parser reads the response type byte via an unbounded 5-byte fetch that returns nullptr, causing type = p[4] to dereference it and crash the client process.
- CVE-2026-87849Medium
A vulnerability in the Discovery naming-service reply parser in Apache bRPC (versions < 1.18.0) calls RapidJSON object-only accessors (FindMember) on JSON values without first validating that they are objects. A malformed Discovery response whose data/service members or instances list contain non-object entries triggers an out-of-bounds read and potentially crashes the bRPC client.
- CVE-2026-86147High
Apache bRPC versions before 1.18.0 expose builtin /flags and /pprof services that allow a remote attacker to change dump paths (bvar_dump_file, bvar_dump_tabs, mbvar_dump_file) and create directories or overwrite files with the server process privileges. Additionally, the ?seconds= parameter in /pprof is not clamped, enabling an attacker to hold the process-wide CPU profiler for an arbitrarily long time.
- CVE-2026-86146High
HTTP request/response smuggling vulnerability in Apache bRPC versions < 1.18.0 stems from inconsistent HTTP/1.1 header parsing in its bundled parser. bRPC accepts malformed header forms (space before colon, spaces in Content-Length values, obs-fold, chunked trailers merged as headers, Transfer-Encoding lists with whitespace), allowing attackers to smuggle requests or headers when bRPC is deployed behind a proxy or load balancer.
Original NVD description (English source)
Interpretation conflict in the HTTP protocol implementation in Apache bRPC (version < 1.18.0) on all platforms allows remote attackers to bypass access control rules enforced by a front proxy. Root Cause: The method dispatch function FindMethodPropertyByURI() in bRPC's HTTP protocol splits the request path with a string splitter that skips empty fields, so paths containing empty path segments (consecutive slashes), such as //flags, /flags// and /flags//port, are dispatched to the same method as their collapsed form /flags. Per RFC 3986 these are distinct paths. A front proxy that enforces an ACL (e.g. blocking access to builtin services such as /flags) matches the collapsed form only, and therefore forwards the padded literal to the bRPC server, where it is dispatched as if it were the collapsed form. This differential allows //flags?setvalue= to reach a builtin service that /flags is not allowed to reach. Additionally, the HTTP/2 implementation never validated the :path pseudo-header, so requests without a :path, or with a :path that neither begins with '/' nor is the asterisk-form '*', contrary to RFC 9113 section 8.3.1, were not rejected. Affected Scenarios: Deployments of Apache bRPC behind a front proxy or gateway that performs access control (ACL) decisions on the literal request path, where the bRPC server accepts HTTP or HTTP/2 traffic from that proxy. In such deployments an attacker can send a path containing empty path segments to reach a resource that the front proxy intended to block. 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/3512 Note: After applying the fix, HTTP and HTTP/2 request paths containing empty path segments (consecutive slashes) are rejected by default, and HTTP/2 :path values that are empty or neither begin with '/' nor equal '*' are rejected. Deployments that depend on the previous lenient behavior can restore it by turning on the gflag -http_allow_empty_path_segments, which is not recommended for servers exposed to untrusted traffic.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS

