How severe is CVE-2026-84304?

No CVSS score has been assigned to CVE-2026-84304 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-84304?

CVE-2026-84304 affects the following packages: google.golang.org/grpc (Go). Ecosystems affected: Go.

How do I fix CVE-2026-84304?

Update google.golang.org/grpc to 1.83.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-84304 is resolved across your whole dependency graph.

How do I detect CVE-2026-84304 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for google.golang.org/grpc, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-84304 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2026-84304 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-84304 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-84304?

CVE-2026-84304 has an EPSS (Exploit Prediction Scoring System) score of 0.6%, placing it in the 48th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-84304?

CVE-2026-84304 is classified as Uncontrolled Resource Consumption (CWE-400). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-84304 published, and has it been updated?

CVE-2026-84304 was published on September 1, 2026 and was last updated on October 17, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

Not in CISA KEV

CVE-2026-84304 — grpc

Fix: grpc/grpc-go@7354d9c

CVE-2026-84304 is a Uncontrolled Resource Consumption vulnerability in google.golang.org/grpc. A fix is available for google.golang.org/grpc — see the affected versions and patch details below.

gRPC-Go: Heap Memory Exhaustion (OOM) via HTTP/2 DATA Frame Fragmentation

Also known asGHSA-vp52-pcj8-j9qcGO-2026-6348

Published

Sep 1, 2026

Updated

Oct 17, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 16, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-84304.

EPSS Exploitation Probability

via FIRST.org ↗

0.6%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs48th percentile — riskier than 48% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐹google.golang.org/grpc

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Impact

An unauthenticated remote attacker can initiate a gRPC stream and purposefully fragment their payload into millions of tiny (e.g., 1-byte) HTTP/2 DATA frames. Even if the total payload volume falls within the configured connection and stream flow-control windows, each independent fragment incurs memory overhead due to internal tracking structures and queue allocation.

Repeated fragmentation massively inflates the heap space consumed by the stream. An attacker multiplexing multiple concurrent streams can exhaust the memory bounds of the runtime, forcing a runtime panic or OutOfMemory condition and leading to a remote Denial of Service (DoS).

Patches

The change to fix this issue is merged in master and a patch release, 1.83.1, has been published that contains this fix.

Workarounds

This vulnerability is mitigated by implementing receive buffer compaction. Consecutive small data buffers are automatically coalesced into larger buffers from a shared pool once the overhead is perceived to be excessive relative to actual payload data, drastically minimizing per-frame memory overheads.

This behavior is enabled by default. A temporary escape hatch is provided via the environment variable GRPC_GO_EXPERIMENTAL_ENABLE_RECEIVE_BUFFER_COMPACTION=false to disable the feature if unforeseen issues arise, but it will be removed in a future release.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`google.golang.org/grpc`	all versions	1.83.1`go get google.golang.org/grpc@v1.83.1`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for google.golang.org/grpc, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update google.golang.org/grpc to 1.83.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-84304 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

Product	Fixed in	Advisory
Cert Manager support for Red Hat OpenShift release 1.17	`cert-manager/jetstack-cert-manager-acmesolver-rhel9:1791371080`	RHSA-2026:82304
Cert Manager support for Red Hat OpenShift release 1.17	`cert-manager/cert-manager-operator-rhel9:1791788287`	RHSA-2026:82322
Red Hat Advanced Cluster Security for Kubernetes 4.11	`advanced-cluster-security/rhacs-main-rhel9:1791396165`	RHSA-2026:79575

Frequently Asked Questions

### Impact An unauthenticated remote attacker can initiate a gRPC stream and purposefully fragment their payload into millions of tiny (e.g., 1-byte) HTTP/2 DATA frames. Even if the total payload volume falls within the configured connection and stream flow-control windows, each independent fragment incurs memory overhead due to internal tracking structures and queue allocation. Repeated fragmentation massively inflates the heap space consumed by the stream. An attacker multiplexing multiple concurrent streams can exhaust the memory bounds of the runtime, forcing a runtime panic or OutOfMemor