GHSA-v5hw-cv9c-rpg7 — high GitHub Advisory (CVE-2026-35457) in rust/libp2p-rendezvous

Description

Summary

The rendezvous server stores pagination cookies without bounds. An unauthenticated peer can repeatedly issue DISCOVER requests and force unbounded memory growth.

Details

Pagination state is stored in:

HashMap&lt;Cookie, HashSet&lt;RegistrationId&gt;&gt;

On Message::Discover:

remote peer
→ DISCOVER
→ handle_request
→ registrations.get(...)
→ new cookie generated
→ cookie inserted into Registrations::cookies

There is no upper bound or eviction policy, so repeated DISCOVER requests grow this map indefinitely.

PoC

A reproduction test and minimal harness will be provided in a private fork in a follow-up comment.

Impact

Remote state amplification leading to memory exhaustion.

Properties:

etwork reachable
no authentication required
low attack complexity
protocol-compliant traffic

Impacts rendezvous nodes exposed to untrusted peers.

Possible Fixes

Global cap + eviction

Bound cookie storage (MAX_COOKIES_TRACKED) with FIFO/expiry aware eviction.
Tradeoff: attacker can churn cookies and evict legitimate pagination state.

Stateless cookies

Encode pagination state in authenticated cookies instead of storing server-side state.
Tradeoff: more complex implementation.

Rate limiting / per-peer quotas

Limit cookie creation per peer.
Tradeoff: requires peer tracking.

Basic information

Type: reviewed
Severity: high
Advisory on GitHub: Open advisory ↗
Repository advisory: Open repository advisory ↗
Source code: Browse source ↗
Published (advisory): 2026-04-04 06:34:29 UTC
Updated: 2026-04-07 19:59:52 UTC
GitHub reviewed: 2026-04-04 06:34:29 UTC
NVD published: 2026-04-07

Score	Percentile
0.05%	16.41%

CVSS Scores

Base score	Version	Severity	Vector
8.2	3.1	—	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:L) Attackers could change some data, but it’s limited—not everything goes. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.

Identifiers

Type	Value
GHSA	GHSA-v5hw-cv9c-rpg7 ↗
CVE	CVE-2026-35457 ↗

CWEs

CWE id	Name
CWE-770	Allocation of Resources Without Limits or Throttling

Credits

failuresmith (reporter)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem	Package	Vulnerable range	First patched	Vulnerable functions
rust	libp2p-rendezvous	< 0.17.1	0.17.1	—

libp2p-rendezvous: Unbounded rendezvous DISCOVER cookies enable remote memory exhaustion