CVE-2025-29908: Netty QUIC hash collision DoS attack

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-03-31 · updated 2026-06-17
Weakness: CWE-407

Description

Netty QUIC codec is a QUIC codec for netty which makes use of quiche. An issue was discovered in the codec. A hash collision vulnerability (in the hash map used to manage connections) allows remote attackers to cause a considerable CPU load on the server (a Hash DoS attack) by initiating connections with colliding Source Connection IDs (SCIDs). This vulnerability is fixed in 0.0.71.Final.

Affected products

netty-incubator-codec-quic: before 0.0.71.Final

References

https://github.com/ncc-pbottine/QUIC-Hash-Dos-Advisory
https://github.com/netty/netty-incubator-codec-quic/commit/e059bd9b78723f8b035e0c547e42ce263f03461c
https://github.com/netty/netty-incubator-codec-quic/security/advisories/GHSA-hqqc-jr88-p6x2

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