CyberSecBulletin
CVE-2026-74758NVD status: Deferred

Apache bRPC: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-74758 is a high-severity use after free vulnerability in Apache bRPC from Apache, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 1.18.0 as the first without the flaw, so updating Apache bRPC to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.65% chance of exploitation within 30 days, higher than 52% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Apache bRPC to 1.18.0 or a later version.
  2. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
ApacheApache bRPCbefore 1.18.01.18.0

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CISA (ADP).

Official 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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

How developers prevent this class of flaw

  • Choose a language that provides automatic memory management.
  • When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.

More Use After Free vulnerabilities (CWE-416)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in Apache bRPC

All Apache bRPC vulnerabilities

Recent Use After Free vulnerabilities

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