GHSA-vp52-pcj8-j9qc CVE-2026-84304 GO-2026-6348
gRPC-Go: Heap Memory Exhaustion (OOM) via HTTP/2 DATA Frame Fragmentation
- Severity
- 8.7 / 10
- High · CVSS 4.0
- Exploit chance (EPSS)
- 0.61%
- Chance of exploitation in the next 30 days. Higher than 49.16% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-400 Uncontrolled Resource Consumption
- Fix
1.83.1- Upgrade google.golang.org/grpc to this version or later
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 versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| google.golang.org/grpc | <= 1.83.0 |
No fix yet |
| google.golang.org/grpc | < 1.83.1 |
1.83.1 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
google.golang.org/grpc Go → 1.83.1
- go
go get google.golang.org/grpc@v1.83.1 && go mod tidy
Severity breakdown
CVSS 4.0 8.7
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- None
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- High
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
Weakness
CWE-400: Uncontrolled Resource Consumption
The product does not properly control the allocation and maintenance of a limited resource.
How to prevent it
- Architecture and Design: Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place. The login application should be protected against DoS attacks as much as possible. Limiting the database access, perhaps by caching result sets, can help minimize the resources expended. To further limit the potential for a DoS attack, consider tracking the rate of requests received from users and blocking requests that exceed a defined rate threshold.
- Architecture and Design: Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed. The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question. The second solution is simply difficult to effectively institute -- and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.
- Architecture and Design: Ensure that protocols have specific limits of scale placed on them.
- Implementation: Ensure that all failures in resource allocation place the system into a safe posture.
References
Advisories
Fixes and patches
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-m425-mq94-257g gRPC-Go HTTP/2 Rapid Reset vulnerability | High Known exploited | Also affects google.golang.org/grpc |
| GHSA-2v4p-qf9q-27wj gRPC-Go xDS servers: Denial of Service (DoS) via crash due to missing `:authority` and `Host` headers | High | Also affects google.golang.org/grpc |
| GHSA-qc2q-p7wx-3px3 gRPC-Go: xDS RBAC HTTP Filter bypass via mixed-case Header Matching and gRFC A41 validation evasion | Medium | Also affects google.golang.org/grpc |
| GHSA-hrxh-6v49-42gf gRPC-Go: xDS RBAC and HTTP/2 Vulnerabilities | High | Also affects google.golang.org/grpc |
| GHSA-p77j-4mvh-x3m3 gRPC-Go has an authorization bypass via missing leading slash in :path | Critical | Also affects google.golang.org/grpc |
| GHSA-xr7q-jx4m-x55m Private tokens could appear in logs if context containing gRPC metadata is logged in github.com/grpc/grpc-go | Low | Also affects google.golang.org/grpc |
| GHSA-cggf-277g-3q54 pypdf has possible large memory usage when parsing page tree | High | Same weakness, CWE-400 |
| GHSA-3g3m-2fjr-6pw4 Glob: AbortSignal cancellation bypass allows post-timeout filesystem traversal | Medium | Same weakness, CWE-400 |
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