CVE-2026-87849 Apache bRPC: Out-of-bounds read via non-object fields in Discovery naming-service reply parsing
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-87849?
CVE-2026-87849 is a medium-severity vulnerability in Apache bRPC, published on 21 Oct 2026.
Official description
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 those values are objects. A malformed Discovery response whose data/service members or instances list contain non-object entries (e.g. a bare integer) triggers the RapidJSON object-access precondition on the client, reading memory out of bounds and potentially crashing the bRPC client.
Root Cause: In src/brpc/policy/discovery_naming_service.cpp, DiscoveryNamingService::GetServers() and DiscoveryNames::ListDiscoveryNodes() access JSON values with member functions on non-object values. RapidJSON only defines these operations for object types; invoking them on a non-object violates the class invariant and results in undefined behavior (out-of-bounds read), commonly crashing the process.
Affected Scenarios: An operator-configured (or compromised) Discovery backend returns a malformed /discovery/nodes or /discovery/fetchs response whose data/service/instance entries are not JSON objects, crashing any bRPC client that refreshes its server list.
How to Fix: 1. Upgrade bRPC to version 1.18.0 or later, which fixes this issue. 2. Apply this patch: https://github.com/apache/brpc/pull/3533
The fix validates that the Discovery response data, per-service data, and instance entries are JSON objects (and skips non-object node/instance entries and rejects non-object data/service values) before calling member accessors.
Weakness: CWE-125
Which versions are affected by CVE-2026-87849?
How do I fix CVE-2026-87849?
No fix has been published for CVE-2026-87849 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-87849 being exploited?
There is no known exploitation of CVE-2026-87849 in the wild and no public exploit code.
Sources
Also known as GHSA-xg38-r433-2m2c.