libp2p-rust: Gossipsub PRUNE.backoff Duration Overflow

published 2026-03-18 7 mo ago modified 2026-06-17 4 mo ago also GHSA-gc42-3jg7-rxr2 , EUVD-2026-13581

cvss: 7.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits: 0; none known

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.

Patch / fix

fixed in 2

crates.io libp2p-gossipsub 0.49.3
protocol libp2p-gossipsub 0.49.3

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 7 mo ago (2026-03-20)

Exploit prediction

0.60% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.7	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
CNA	4.0	8.7	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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem	package	affected	fixed in
crates.io	libp2p-gossipsub	<0.49.3	0.49.3

Affected products

libp2p rust-libp2p

Classification

Weakness

CWE-190 Integer Overflow or Wraparound

References

github.com /libp2p/rust-libp2p/security/advisories/GHSA-gc42-3jg7-rxr2
web, vendor-advisory
nvd.nist.gov /vuln/detail/CVE-2026-33040
advisory
github.com /libp2p/rust-libp2p
package

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary