CVE-2026-74758: Apache bRPC: Heap Use-After-Free in RTMP Abort Message Handling

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-21 · updated 2026-10-30
Weakness: CWE-416

Description

A heap use-after-free in the RTMP protocol component of Apache bRPC (versions < 1.18.0) allows a remote attacker to crash a bRPC RTMP server by sending a crafted Abort control message. No authentication or application-level request is required. Root Cause: When an RTMP Abort control message names the chunk stream that is currently being parsed (the chunk stream carrying the message itself), RtmpChunkStream::OnAbortMessage calls RtmpContext::ClearChunkStream, which deletes the RtmpChunkStream while its Feed() is still running. After the message handler returns, Feed() continues to access members of the deleted object, resulting in a heap-use-after-free. Affected Scenarios: bRPC servers that enable RTMP support (ServerOptions.rtmp_service set) and accept connections from untrusted networks. How to Fix: 1. Upgrade bRPC to version 1.18.0, which fixes this issue. 2. Apply this patch: https://github.com/apache/brpc/pull/3452 The fix skips clearing the chunk stream when the Abort message targets the chunk stream that is currently being parsed.

Affected products

Apache Software Foundation Apache bRPC: before 1.18.0 — fixed in 1.18.0

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache bRPC 1.18.0. Check the vendor advisory for mitigations.

References

https://lists.apache.org/thread/2pf15ojj0vr7rtx95677kgtl1mx3gdgb

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