libp2p-rendezvous: Unlimited namespace registrations per peer enables OOM DoS on rendezvous servers

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2026-35405: 0.40% estimated exploitation activity in the next 30 days; percentile 33.78 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary found that 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. no auth required. any peer on the network can do this. Details the bug is in Registrations::add() inside protocols/rendezvous/src/server.rs. the store uses a BiMap keyed on (PeerId, Namespace) so yes, a peer can't register the same namespace twice. but there's nothing stopping it from registering 10,000 different namespaces. each unique one gets its own entry in: - registrationsforpeer (BiMap) - registrations (HashMap) - nextexpiry (FuturesUnordered a new heap-allocated BoxFuture per registration) namespace strings are only validated for length (MAXNAMESPACE = 255), not count. there's no…

Published by the source

4 Apr 2026, 06:33 UTC

Last modified by the source

9 Jun 2026, 10:38 UTC

Source last checked

26 Oct 2026, 15:42 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-cqfx-gf56-8x59

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# Patch Next advisory brief: CVE-2026-35405

Advisory: libp2p-rendezvous: Unlimited namespace registrations per peer enables OOM DoS on rendezvous servers
IDs: CVE-2026-35405, GHSA-cqfx-gf56-8x59
Record: https://patchnext.com/advisories/cve-2026-35405 (revision 1, source checked 26 Oct 2026, 15:42 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: libp2p-rendezvous 0.17.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io libp2p-rendezvous: affected < 0.17.1; fixed in 0.17.1

## Suggested inspection (read-only)
- crates.io libp2p-rendezvous: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on libp2p-rendezvous.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-cqfx-gf56-8x59 (GitHub-reviewed advisory GHSA-cqfx-gf56-8x59 lists affected ranges: crates.io libp2p-rendezvous >=0 <0.17.1)

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