CVE-2026-53430 grpc gzip decompression bomb in GRPC.Compressor.Gzip.decompress/1
An unauthenticated remote attacker can cause a denial of service by sending a crafted gzip-compressed gRPC frame that exhausts memory via decompression bomb.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-53430?
CVE-2026-53430 is a high-severity denial of service vulnerability in elixir-grpc grpc, published on 15 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in elixir-grpc grpc (GRPC.Compressor.Gzip, GRPC.Message modules) allows a denial of service via a gzip decompression bomb.
This vulnerability is associated with program files lib/grpc/compressor/gzip.ex, lib/grpc/message.ex and program routines 'Elixir.GRPC.Compressor.Gzip':decompress/1, 'Elixir.GRPC.Message':from_data/2.
'Elixir.GRPC.Compressor.Gzip':decompress/1 calls :zlib.gunzip/1 directly on attacker-controlled bytes with no decompressed-size limit, ratio check, or incremental decoding. Because this module is the registered gzip GRPC.Compressor implementation, it is invoked automatically whenever an incoming gRPC frame carries the grpc-encoding: gzip header. :zlib.gunzip/1 allocates the entire decompressed result as a single binary, so a small highly compressible payload (for example a few kilobytes of zeros, which gzip compresses at roughly 1000:1) expands to multiple gigabytes inside a single call. The max_receive_message_length limit is enforced only against the already-decompressed message, so it provides no protection. An unauthenticated remote peer can send a single crafted frame to exhaust the BEAM node's heap and trigger an out-of-memory kill.
This issue affects grpc: from 0.4.0 before 1.0.0.
Weakness: CWE-409
Which versions are affected by CVE-2026-53430?
3 open source packages ship an affected version, including grpc.
| Package | Affected | Fixed in |
|---|---|---|
grpc Hex | From 0.4.0 | 1.0.0 |
grpc Hex | From 0.4.0 | 1.0.0 |
grpc Hex | From 0.4.0 | 1.0.0 |
How do I fix CVE-2026-53430?
Upgrade grpc to 1.0.0 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-53430 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-53430 exists.
Sources
Also known as EEF-CVE-2026-53430, GHSA-6ccx-9c9f-327w.