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VulnerabilityPublished

CVE-2026-33040: rust-libp2p · Integer Overflow or Wraparound

Affects rust-libp2pSource CVE Database V5

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Not known to be exploited · CVSS 8.7 High : upgrade to 0.49.3 soon.

Data as of 31 Oct 2026, 08:20 UTC

CVSS 4.0 base score
8.7High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 48% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 0.49.3
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

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 20 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Upgrade rust-libp2p and libp2p/rust-libp2p to 0.49.3.

Affected software

ProductAffectedFixed in
libp2prust-libp2pAffected
  • <0.49.3
Fixed in
  • 0.49.3
crates.iolibp2p/rust-libp2ppkg:cargo/libp2p/rust-libp2pOther threatsAffected
  • <0.49.3
Fixed in
  • 0.49.3

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate this vulnerability, organizations should upgrade rust-libp2p to version 0.49.3 or later, where the overflow issue is fixed. If immediate upgrade is not possible, implement network-level controls to restrict access to libp2p Gossipsub listener ports, limiting exposure to untrusted networks and potential attackers. Monitoring and alerting on unexpected connection attempts or malformed PRUNE control messages can help detect exploitation attempts. Additionally, consider implementing application-level rate limiting or connection throttling to reduce the impact of repeated attack attempts. Developers should audit any custom handling of backoff or timing values in their libp2p integrations to ensure proper validation and error handling. Finally, maintain awareness of updates from the rust-libp2p project and apply security patches promptly.

Description

libp2p-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.

References

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