# CVE-2026-48853: Remote code execution and denial of service via unsafe Erlang term deserialization in elixir-grpc/grpc

> Unauthenticated attackers can cause denial of service or remote code execution via unsafe Erlang term deserialization in the Elixir gRPC library.

- **Severity:** Critical 9.2 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Jun 2026
- **Updated:** 24 Sep 2026
- **Also known as:** EEF-CVE-2026-48853, GHSA-grp7-v8xh-rj7h, UBUNTU-CVE-2026-48853

## What is CVE-2026-48853?

CVE-2026-48853 is a critical unsafe deserialization 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

Deserialization of Untrusted Data and Allocation of Resources Without Limits or Throttling vulnerabilities in elixir-grpc grpc allow unauthenticated attackers to crash the BEAM node via atom table exhaustion and, when a decoded term flows into a call site that invokes it, achieve remote code execution on the server.

'Elixir.GRPC.Codec.Erlpack':decode/2 (lib/grpc/codec/erlpack.ex) calls :erlang.binary_to_term/1 on the raw gRPC message body without the :safe option, no size bound, and no type guard. Any unauthenticated peer that sends a request with Content-Type: application/grpc+erlpack can send a crafted payload that mints arbitrary new atoms (which are never garbage-collected, exhausting the bounded atom table and crashing the VM) or that encodes a fun term which, if applied anywhere downstream, executes attacker-controlled code inside the server process.

This issue affects grpc: from 0.4.0 before 1.0.0.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling), CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2026-48853?

3 open source packages ship an affected version, including grpc.


| Package | Ecosystem | 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-2026-48853?

Upgrade grpc to 1.0.0 or later.

## Is CVE-2026-48853 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-48853 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-48853 and fix it if it is affected.

What it is: CVE-2026-48853 is a critical unsafe deserialization 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.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-48853 exists.

Affected packages and fixed versions:
- grpc (Hex): affected from 0.4.0; fixed in 1.0.0
- grpc (Hex): affected from 0.4.0; fixed in 1.0.0
- grpc (Hex): affected from 0.4.0; fixed in 1.0.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-48853/ (Markdown: https://insights.sbomify.com/CVE-2026-48853/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-48853
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-48853
- OSV: https://osv.dev/vulnerability/CVE-2026-48853

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-48853/
Summaries are generated and may contain mistakes; the official description above is the record.