# CVE-2026-35405: libp2p-rendezvous: Unlimited namespace registrations per peer enables OOM DoS on rendezvous servers

> A malicious peer can exhaust server memory by registering unlimited namespaces, causing an out-of-memory denial of service in libp2p rendezvous servers.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 7 Apr 2026
- **Updated:** 9 Apr 2026
- **Also known as:** GHSA-cqfx-gf56-8x59

## What is CVE-2026-35405?

CVE-2026-35405 is a high-severity denial of service vulnerability in rust-libp2p, published on 7 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

libp2p-rust is the official rust language Implementation of the libp2p networking stack. Prior to 0.17.1, libp2p-rendezvous server has no limit on how many namespaces a single peer can register.  A malicious peer can just keep registering unique namespaces in a loop and the server happily accepts every single one allocating memory for each registration with no pushback. Keep doing this long enough (or with multiple sybil peers) and the server process gets OOM killed. This vulnerability is fixed in 0.17.1.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2026-35405?

2 open source packages ship an affected version, including libp2p-rendezvous. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `libp2p-rendezvous` | crates.io | All versions | 0.17.1 |
| `libp2p-rendezvous` | crates.io | All versions | 0.17.1 |

Products: Protocol Libp2p.

## How do I fix CVE-2026-35405?

Upgrade libp2p-rendezvous to 0.17.1 or later.

## Is CVE-2026-35405 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-35405 exists.

## Other vulnerabilities in rust-libp2p

- [CVE-2026-35457](https://insights.sbomify.com/CVE-2026-35457/): libp2p-rust has unbounded rendezvous DISCOVER cookies enable remote memory exhaustion (high 8.2)
- [CVE-2023-40583](https://insights.sbomify.com/CVE-2023-40583/): libp2p nodes vulnerable to OOM attack (high 7.5)
- [CVE-2022-23492](https://insights.sbomify.com/CVE-2022-23492/): go-libp2p denial of service vulnerability from lack of resource management (high 7.5)
- [CVE-2022-23486](https://insights.sbomify.com/CVE-2022-23486/): libp2p-rust denial of service vulnerability from lack of resource management (high 7.5)
- [CVE-2022-23487](https://insights.sbomify.com/CVE-2022-23487/): libp2p denial of service vulnerability from lack of resource management (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-35405 and fix it if it is affected.

What it is: CVE-2026-35405 is a high-severity denial of service vulnerability in rust-libp2p, published on 7 Apr 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-2026-35405 exists.

Affected packages and fixed versions:
- libp2p-rendezvous (crates.io): affected all versions; fixed in 0.17.1
- libp2p-rendezvous (crates.io): affected all versions; fixed in 0.17.1

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-2026-35405/ (Markdown: https://insights.sbomify.com/CVE-2026-35405/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-35405
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-35405
- OSV: https://osv.dev/vulnerability/CVE-2026-35405

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-35405/
Summaries are generated and may contain mistakes; the official description above is the record.