High

libp2p-rust Gossipsub PRUNE backoff overflow DoS

IdentifiersCVE-2026-33040CWE-190· Integer Overflow or Wraparound

CVE-2026-33040 affects libp2p-rust, the official Rust implementation of the libp2p networking stack, in versions prior to 0.49.3. The flaw is in the Gossipsub implementation's handling of PRUNE control messages: it accepts attacker-controlled backoff values and performs unchecked time arithmetic when updating and storing backoff state. By sending a specially crafted PRUNE message containing an extremely large backoff value, such as u64::MAX, a remote attacker can trigger Duration/Instant overflow in the backoff update logic. This overflow causes a panic in the networking state machine, terminating or crashing the affected application path. The issue is remotely reachable over a normal libp2p connection and does not require authentication.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation causes a denial of service. A remote, unauthenticated network attacker that can reach an exposed libp2p Gossipsub listener can crash an affected application by forcing a panic in the networking state machine. Because the attack can be repeated by reconnecting and replaying the crafted PRUNE control message, the attacker can repeatedly disrupt service availability. Based on the provided information, the impact is limited to availability loss; no confidentiality or integrity impact is described.

Mitigation

If you can’t patch tonight, do this now.

If immediate upgrade is not possible, reduce exposure by restricting network access to libp2p Gossipsub listeners to trusted peers or trusted network segments, and disable or avoid the affected Gossipsub functionality or code path where operationally feasible. Because exploitation is unauthenticated and delivered over a normal libp2p connection, network-level access controls are the most practical temporary mitigation until patched versions can be deployed.

Remediation

Patch, then assume compromise.

Upgrade libp2p-rust to version 0.49.3 or later, which fixes the vulnerable Gossipsub backoff-handling logic. Ensure all applications and dependencies embedding affected libp2p-rust versions prior to 0.49.3 are rebuilt and redeployed with the patched release.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

Libp2pLibp2p-Gossipsubapplication

ProtocolLibp2papplication

ProtocolLibp2p-Gossipsubapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

2 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

2 SOURCESView more in app

cvefeed high severityNews

Mar 20, 2026

CVE-2026-33040 - libp2p-rust: Gossipsub PRUNE.backoff Duration Overflow

A remotely reachable denial-of-service vulnerability in libp2p-rust Gossipsub where attacker-controlled PRUNE backoff values can trigger unchecked time arithmetic overflow and panic the networking state machine.

What this page doesn’t show

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity1

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2026-33040

NVD

nvd.nist.gov/vuln/detail/CVE-2026-33040

MITRE CWE · CWE-190

Integer Overflow or Wraparound

Vendor Advisory

github.com/libp2p/rust-libp2p/security/advisories/GHSA-gc42-3jg7-rxr2

libp2p-rust Gossipsub PRUNE backoff overflow DoS

IdentifiersCVE-2026-33040CWE-190· Integer Overflow or Wraparound