Inefficient algorithmic complexity in Netty QUIC codec

1) Inefficient Algorithmic Complexity

EUVDB-ID: #VU109895

Risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2025-29908

CWE-ID: CWE-407 - Inefficient Algorithmic Complexity

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a hash collision vulnerability in the hash map used to manage connections. A remote attacker can cause a considerable CPU load on the server (a Hash DoS attack) by initiating connections with colliding Source Connection IDs (SCIDs)

Mitigation

Install update from vendor's website.

Vulnerable software versions

netty-incubator-codec-quic: 0.0.1 - 0.0.70

CPE2.3

• cpe:2.3:a:netty:netty-incubator-codec-quic:0.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty-incubator-codec-quic:0.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty-incubator-codec-quic:0.0.3:*:*:*:*:*:*:*

External links

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

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.