How severe is CVE-2026-34219?

CVE-2026-34219 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-34219 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (25th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-34219?

CVE-2026-34219 affects Protocol Libp2p-gossipsub. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-34219?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-34219 have an EU (EUVD) identifier?

Yes. CVE-2026-34219 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-17521.

When was CVE-2026-34219 published?

CVE-2026-34219 was published on 2026-03-31 and last updated on 2026-06-17.

CVE-2026-34219

CVE-2026-34219 is a medium-severity vulnerability in Protocol Libp2p-gossipsub with a CVSS 3.x base score of 5.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-190.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
CVSS v4: 8.2
EPSS exploit prediction: 0% (25th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-17521
Weakness: CWE-190
Affected product: Protocol Libp2p-gossipsub
Published: 2026-03-31
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-34219?: 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.
How severe is CVE-2026-34219?: CVE-2026-34219 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-34219 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (25th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-34219?: CVE-2026-34219 affects Protocol Libp2p-gossipsub. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-34219?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-34219 have an EU (EUVD) identifier?: Yes. CVE-2026-34219 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-17521.
When was CVE-2026-34219 published?: CVE-2026-34219 was published on 2026-03-31 and last updated on 2026-06-17.

References

https://github.com/libp2p/rust-libp2p/security/advisories/GHSA-xqmp-fxgv-xvq5

Affected products (1)

cpe:2.3:a:protocol:libp2p-gossipsub:*:*:*:*:*:rust:*:*

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