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VulnerabilityPublished

CVE-2026-34219: rust-libp2p · Integer Overflow or Wraparound

Affects rust-libp2pSource CVE Database V5

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Not known to be exploited · CVSS 8.2 High : upgrade to 0.49.4 soon.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 4.0 base score
8.2High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 47% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 0.49.4
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 31 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 0.49.4.

Affected software

ProductAffectedFixed in
libp2prust-libp2pAffected
  • <0.49.4
Fixed in
  • 0.49.4
crates.iolibp2p/rust-libp2ppkg:cargo/libp2p/rust-libp2pOther threatsAffected
  • <0.49.4
Fixed in
  • 0.49.4

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

AI-suggested

The primary mitigation is to upgrade all rust-libp2p deployments to version 0.49.4 or later, where the vulnerability has been fixed. For environments where immediate upgrade is not feasible, implement network-level controls to restrict peer connections to trusted entities and monitor for anomalous PRUNE control messages with unusually large backoff values. Employ runtime monitoring and alerting on process panics or crashes related to libp2p components to enable rapid incident response. Consider implementing application-layer rate limiting or filtering of control messages to reduce exposure. Additionally, conduct thorough code reviews and fuzz testing on custom libp2p protocol extensions to detect similar integer overflow issues. Maintain up-to-date dependency management and vulnerability scanning to promptly identify and remediate vulnerable versions in development and production pipelines.

Description

libp2p-rust is the official rust language Implementation of the libp2p networking stack. Prior to version 0.49.4, the Rust libp2p Gossipsub implementation contains a remotely reachable panic in backoff expiry handling. After a peer sends a crafted PRUNE control message with an attacker-controlled, near-maximum backoff value, the value is accepted and stored as an Instant near the representable upper bound. On a later heartbeat, the implementation performs unchecked Instant + Duration arithmetic (backoff_time + slack), which can overflow and panic with: overflow when adding duration to instant. This issue is reachable from any Gossipsub peer over normal TCP + Noise + mplex/yamux connectivity and requires no further authentication beyond becoming a protocol peer. This issue has been patched in version 0.49.4.

References

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