GHSA-GC42-3JG7-RXR2
Vulnerability from github – Published: 2026-03-18 19:54 – Updated: 2026-03-20 21:23Summary
The Rust libp2p Gossipsub implementation accepts attacker-controlled PRUNE backoff values and may perform unchecked time arithmetic when storing backoff state. A specially crafted PRUNE control message with an extremely large backoff (e.g. u64::MAX) can lead to Duration/Instant overflow during backoff update logic, triggering a panic in the networking state machine. This is remotely reachable over a normal libp2p connection and does not require authentication.
Attack Scenario
An attacker that can establish a libp2p Gossipsub session with a target node can crash the target by sending a single crafted PRUNE control message: 1. Establish a standard libp2p transport session and negotiate a stream multiplexer. 2. Open a Gossipsub stream and negotiate the meshsub protocol. 3. Send one protobuf RPC containing ControlPrune with a very large backoff value (e.g. 18446744073709551615 / u64::MAX). When processed, the oversized backoff can reach time-update logic that adds Duration::from_secs(backoff) to Instant::now(), causing overflow and panic.
Impact
Remote unauthenticated denial of service. Any application exposing a libp2p Gossipsub listener and using the affected backoff-handling path can be crashed by a network attacker that can reach the service port. The attack can be repeated by reconnecting and replaying the crafted control message.
Patches
Users should upgrade to a release that hardens Gossipsub backoff handling.
This vulnerability was originally submitted by @revofusion to the Ethereum Foundation bug bounty program
{
"affected": [
{
"package": {
"ecosystem": "crates.io",
"name": "libp2p-gossipsub"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.49.3"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-33040"
],
"database_specific": {
"cwe_ids": [
"CWE-190"
],
"github_reviewed": true,
"github_reviewed_at": "2026-03-18T19:54:12Z",
"nvd_published_at": "2026-03-20T06:16:12Z",
"severity": "HIGH"
},
"details": "### Summary\nThe Rust libp2p Gossipsub implementation accepts attacker-controlled PRUNE backoff values and may perform unchecked time arithmetic when storing backoff state.\nA specially crafted PRUNE control message with an extremely large backoff (e.g. u64::MAX) can lead to Duration/Instant overflow during backoff update logic, triggering a panic in the networking state machine. This is remotely reachable over a normal libp2p connection and does not require authentication.\n\n### Attack Scenario\nAn attacker that can establish a libp2p Gossipsub session with a target node can crash the target by sending a single crafted PRUNE control message:\n1. Establish a standard libp2p transport session and negotiate a stream multiplexer.\n2. Open a Gossipsub stream and negotiate the meshsub protocol.\n3. Send one protobuf RPC containing ControlPrune with a very large backoff value (e.g. 18446744073709551615 / u64::MAX).\nWhen processed, the oversized backoff can reach time-update logic that adds Duration::from_secs(backoff) to Instant::now(), causing overflow and panic.\n\n### Impact\nRemote unauthenticated denial of service.\nAny application exposing a libp2p Gossipsub listener and using the affected backoff-handling path can be crashed by a network attacker that can reach the service port. The attack can be repeated by reconnecting and replaying the crafted control message.\n### Patches\nUsers should upgrade to a release that hardens Gossipsub backoff handling.\n\nThis vulnerability was originally submitted by @revofusion to the Ethereum Foundation bug bounty program",
"id": "GHSA-gc42-3jg7-rxr2",
"modified": "2026-03-20T21:23:14Z",
"published": "2026-03-18T19:54:12Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/libp2p/rust-libp2p/security/advisories/GHSA-gc42-3jg7-rxr2"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33040"
},
{
"type": "PACKAGE",
"url": "https://github.com/libp2p/rust-libp2p"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "Gossipsub PRUNE.backoff Duration Overflow"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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- Confirmed: The vulnerability has been validated from an analyst's perspective.
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- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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