CVE - CVE-2025-24356

CVE-ID
CVE-2025-24356	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
Description
fastd is a VPN daemon which tunnels IP packets and Ethernet frames over UDP. When receiving a data packet from an unknown IP address/port combination, fastd will assume that one of its connected peers has moved to a new address and initiate a reconnect by sending a handshake packet. This "fast reconnect" avoids having to wait for a session timeout (up to ~90s) until a new connection is established. Even a 1-byte UDP packet just containing the fastd packet type header can trigger a much larger handshake packet (~150 bytes of UDP payload). Including IPv4 and UDP headers, the resulting amplification factor is roughly 12-13. By sending data packets with a spoofed source address to fastd instances reachable on the internet, this amplification of UDP traffic might be used to facilitate a Distributed Denial of Service attack. This vulnerability is fixed in v23.
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://github.com/neocturne/fastd/commit/1f233bee76b722c0b3f9024f2c39c72e9f7e5843 URL:https://github.com/neocturne/fastd/commit/1f233bee76b722c0b3f9024f2c39c72e9f7e5843 MISC:https://github.com/neocturne/fastd/commit/3940150e801d0c91460491bec32cbcc5bbc89d5f URL:https://github.com/neocturne/fastd/commit/3940150e801d0c91460491bec32cbcc5bbc89d5f MISC:https://github.com/neocturne/fastd/commit/5f63fcfc18ae9cad023fa463b152d5e14192b5a8 URL:https://github.com/neocturne/fastd/commit/5f63fcfc18ae9cad023fa463b152d5e14192b5a8 MISC:https://github.com/neocturne/fastd/commit/9df7e516378441d2d17b89f9db5c27c8312d8f12 URL:https://github.com/neocturne/fastd/commit/9df7e516378441d2d17b89f9db5c27c8312d8f12 MISC:https://github.com/neocturne/fastd/commit/c1a07b3f2b9066c3713c68547da700b85d60f4f7 URL:https://github.com/neocturne/fastd/commit/c1a07b3f2b9066c3713c68547da700b85d60f4f7 MISC:https://github.com/neocturne/fastd/commit/ce1b79b12dbfa796743b5f3a50789ade965b7023 URL:https://github.com/neocturne/fastd/commit/ce1b79b12dbfa796743b5f3a50789ade965b7023 MISC:https://github.com/neocturne/fastd/commit/d03a0a17347efb5293e42fde7d982781e90f14ef URL:https://github.com/neocturne/fastd/commit/d03a0a17347efb5293e42fde7d982781e90f14ef MISC:https://github.com/neocturne/fastd/security/advisories/GHSA-pggg-vpfv-4rcv URL:https://github.com/neocturne/fastd/security/advisories/GHSA-pggg-vpfv-4rcv
Assigning CNA
GitHub (maintainer security advisories)
Date Record Created
20250120	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20250120)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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