CVE-2026-84304 and is rated High severity with a CVSS score of 8.7. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.
What to do next
Remediation and response
Microsoft Security Response Center guidance
Vendor revision: Oct 10, 2026
Vendor remediation details
Release Notes
Vendor-listed releases
4.0.2-11
19.0.4-14
2.27.0-15
2.14.1-21
1.30.10-31
1.62.0-8
1.11.4-21
3.5.34-1
1.14.4-13
3.7.0-8
10.25.1-9
1.6.0-3
2.101.0-1
3.32.0.kata0-6
3.15.0.aks0-21
25.0.3-21
1.31.0-33
2.4.0-1
1.32.0-9
0.14.0-18
0.24.2-33
1.8.4-3
1.7.7-18
1.9.5-22
CISA KEVNot listedBased on the latest collected catalog
EPSS0.6%Estimated 30-day exploitation probability
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview
What is CVE-2026-84304?
gRPC-Go is the Go language implementation of gRPC. Prior to 1.83.1, internal/transport/transport.go stores each fragmented HTTP/2 DATA frame as a separate recvMsg in recvBuffer, so millions of one-byte frames can consume disproportionate heap memory even when payload bytes remain within connection and stream flow-control windows.
An unauthenticated remote attacker can use concurrent multiplexed streams to exhaust process memory and cause a runtime panic or out-of-memory termination. Receive-buffer compaction is enabled by default and can be controlled temporarily with GRPC_GO_EXPERIMENTAL_ENABLE_RECEIVE_BUFFER_COMPACTION.