CVE-2026-81755: Apache bRPC: Uncontrolled Resource Consumption via Excessive Streams in a Single RPC Request
Apache Software Foundation · Apache bRPC
Vendor fix available · Affected: Apache Software Foundation Apache bRPC · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 54% of scored CVEs
DescriptionCVE.org
Uncontrolled resource consumption in the streaming RPC component of Apache bRPC (version < 1.18.0) allows a remote attacker to exhaust server memory and cause denial of service by sending a single RPC request that declares an excessive number of streams. Root Cause: In the streaming RPC feature, a client can declare multiple streams in one RPC request by putting extra stream identifiers into the repeated field `stream_settings.extra_stream_ids` of the RPC meta. On the server side, `StreamAccept` creates one response stream for every stream identifier declared by the request, without limiting the number of streams accepted in a single RPC. The request body size is only bounded by `max_body_size` (default 64MB), which is enough to carry millions of stream identifiers. Each accepted stream allocates its own bthread execution queue and associated resources, so a single crafted request can make the server create a huge number of streams and exhaust memory, leading to denial of service. Affected Scenarios: Use a bRPC server that serves streaming RPC and calls `StreamAccept` to accept streams from untrusted clients. How to Fix: (Choose one of the following options) 1. Upgrade bRPC to the 1.18.0 version. 2. Apply this patch: https://github.com/apache/brpc/pull/3493 Note: The fix adds a new gflag `stream_max_streams_per_request` with a default value of 64. Requests declaring more streams than the limit are rejected before any response stream is created. Applications that legitimately need to accept more than 64 streams in one RPC must raise this flag; otherwise such requests will fail after applying the fix.
Affected products1
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- Apache Software Foundation · Apache bRPCbefore 1.18.0
On the Atlas
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- Exploitation
- Unlikely (under 1%). EPSS under 1%, or no score yet.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Published
- October 2026
CoverageNo articles yet
No CyberSIXT article names CVE-2026-81755 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.