# CVE-2026-74758: Apache bRPC heap use-after-free in RTMP protocol

Source: https://junglewise.ai/threats/cve-2026-74758-a-heap-use-after-free-in-the-rtmp-protocol-component-of-apache  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-21. Updated: 2026-10-21  
License: CC BY 4.0 with a link back

CVE-2026-74758 · Severity: info · Published 2026-10-21

Apache bRPC is a high-performance RPC framework used in distributed systems. A heap use-after-free flaw in its RTMP protocol support allows an unauthenticated remote attacker to crash bRPC servers that have RTMP enabled, causing denial of service. This affects servers accepting connections from untrusted networks.

Technologies: [Apache Brpc](https://junglewise.ai/threats/technologies/brpc). Vendors: [Apache](https://junglewise.ai/threats/vendors/apache).

## Quick answers

**Is CVE-2026-74758 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-74758 being exploited in the wild.

**How severe is CVE-2026-74758?** Informational severity, published 21 October 2026.

**Which products and versions are affected?** Apache Brpc < 1.18.0.

**Is there a fix for CVE-2026-74758?** Yes: fixed in 1.18.0. Until then: Disable RTMP support by leaving ServerOptions.rtmp_service unset if the service is not required, or restrict network access to bRPC servers to trusted sources only until an upgrade is possible. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-74758 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-74758?** Check whether you run Apache Brpc at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 1.18.0

Disable RTMP support by leaving ServerOptions.rtmp_service unset if the service is not required, or restrict network access to bRPC servers to trusted sources only until an upgrade is possible.

## Technical details

A heap use-after-free occurs in the RTMP protocol component when an Abort control message targets the chunk stream currently being parsed. RtmpChunkStream::OnAbortMessage calls ClearChunkStream to delete the object while its Feed() method is still executing, leading to access of freed memory. The vulnerability requires no authentication and can be triggered remotely by sending a crafted Abort message.

## Affected products

- Apache bRPC < 1.18.0

## Timeline

- 2026-10-21: disclosed
- 2026-10-21: patched: Fixed in Apache bRPC 1.18.0

## References

- [https://github.com/](https://github.com/)
- [https://lists.apache.org/thread/2pf15ojj0vr7rtx95677kgtl1mx3gdgb](https://lists.apache.org/thread/2pf15ojj0vr7rtx95677kgtl1mx3gdgb)

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