UDP traffic amplification in fastd

1) Asymmetric Resource Consumption (Amplification)

EUVDB-ID: #VU103329

Risk: Low

CVSSv4.0: 1.7 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2025-24356

CWE-ID: CWE-405 - Asymmetric Resource Consumption (Amplification)

Exploit availability: No

Description

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

The vulnerability exists due to an error when handling UDP packets in fast reconnect feature. A remote non-authenticated attacker can send small UDP packets (even a 1-byte packet is enough) to the application and force it to initiate connections to third-party systems using much larger packets.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

fastd: 0.1 - 22

CPE2.3

• cpe:2.3:a:NeoRaider:fastd:0.1:*:*:*:*:*:*:*
• cpe:2.3:a:NeoRaider:fastd:0.2:*:*:*:*:*:*:*
• cpe:2.3:a:NeoRaider:fastd:0.3:*:*:*:*:*:*:*

External links

https://github.com/neocturne/fastd/security/advisories/GHSA-pggg-vpfv-4rcv
https://bugzilla.redhat.com/show_bug.cgi?id=2342133

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.