CVE-2026-80463 Apache bRPC: Unbounded Memory Accumulation in Stream Message Reassembly
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-80463?
CVE-2026-80463 is a vulnerability in Apache bRPC, published on 21 Oct 2026.
Official description
Unbounded memory accumulation in the stream message reassembly path of Apache bRPC (version < 1.18.0) on all platforms allows remote attackers to exhaust the memory of a server (denial of service) by sending an endless sequence of continuation data frames.
Root Cause: The streaming RPC protocol bounds every single data frame by max_body_size, but a fragmented stream message accumulates continuation frames into one buffer (_pending_buf) without any limit on the accumulated size. A malicious peer that can open a stream can therefore keep sending continuation frames to make the receiver accumulate an arbitrarily large in-memory message. Since the default flow-control settings (socket_max_streams_unconsumed_bytes=0) do not throttle the sending rate, the receiver's memory grows until the process runs out of memory and crashes or becomes unavailable.
Affected Scenarios: Services that accept streams from untrusted clients (for example using brpc::StreamAccept or brpc::StreamCreate with the built-in streaming protocol) are affected.
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/3489
Note: The fix limits the accumulated payload of a fragmented stream message to max_body_size (default 64MB). When the accumulated payload exceeds the limit, the pending fragments are released and the stream is closed with error EMSGSIZE. After applying the fix, legitimate fragmented stream messages larger than max_body_size will be rejected; you can adjust the gflag max_body_size to change the limit.
Weakness: CWE-770
Which versions are affected by CVE-2026-80463?
How do I fix CVE-2026-80463?
No fix has been published for CVE-2026-80463 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-80463 being exploited?
There is no known exploitation of CVE-2026-80463 in the wild and no public exploit code.
Sources
Also known as GHSA-h682-23cr-8m53.