Libp2p GossipsubApplication · Protocol
CVE-2026-33040
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedlibp2p-rust is the official rust language Implementation of the libp2p networking stack. In versions prior to 0.49.3, the 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. 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. This issue has been fixed in version 0.49.3.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe libp2p-rust Gossipsub implementation has an integer overflow vulnerability in its backoff handling logic. Attackers can send a specially crafted PRUNE control message with an extremely large backoff value (e.g., u64::MAX) that causes unchecked Duration/Instant arithmetic to overflow, triggering a panic in the networking state machine and crashing the service.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Libp2p GossipsubApplication
< 0.49.3CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify libp2p-rust Gossipsub versionInspect your project's Cargo.lock file or Cargo.toml for the libp2p version, specifically looking for the gossipsub crate. Run 'cargo tree -p libp2p-gossipsub' or 'grep -A5 "name = \"libp2p-gossipsub\"' in Cargo.lock to find the exact versionAffected if The gossipsub crate version is lower than 0.49.3
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Verify Gossipsub protocol is enabledCheck your libp2p node configuration or code to confirm the Gossipsub behaviour/peer protocol is enabled. Look for calls to gossipsub::Behaviour::new or similar Gossipsub configuration in your codebaseAffected if Gossipsub is enabled and the version from step 1 is below 0.49.3
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Confirm network exposure to external peersReview network configuration to determine if your libp2p node accepts connections from untrusted/remote peers. Check for settings like 'noise', authenticated peers, or firewall rules that may limit who can send PRUNE messagesAffected if Untrusted remote peers can connect and send control messages, combined with vulnerable version
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Check for runtime logs indicating panicMonitor application logs for panics related to 'attempt to add with overflow' or 'duration'/'instant' arithmetic errors, particularly when processing gossipsub messagesAffected if Logs show arithmetic overflow panics in gossipsub message handling
You are affected if your environment uses libp2p-gossipsub version below 0.49.3 and has Gossipsub protocol enabled, as processing a PRUNE message with an extremely large backoff value will trigger the overflow and crash the service.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped0.49.3
Upgrade libp2p-rust to version 0.49.3 or later to obtain the patched version. Consider implementing rate limiting on control messages as an additional defense-in-depth measure.
libp2p-rust Gossipsub version 0.49.3
- Update the libp2p-rust dependency in your project to version 0.49.3 or later
- Run `cargo update` or `cargo upgrade libp2p` to fetch the fixed version
- Rebuild and test your application to ensure the update doesn't introduce regressions
- Redeploy the updated application to production environments
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Libp2p Gossipsub
Scoped from the published advisory
- Consultation3.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,416.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-33040 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-33040 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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