CVE-2025-4821 describes an incorrect congestion window growth vulnerability in Cloudflare quiche versions prior to 0.24.4. An unauthenticated remote attacker can manipulate the victim's congestion control state by sending crafted ACK frames, causing the congestion window to grow excessively. This flaw has a CVSS score of 7.5 (HIGH) due to its network attack vector, low attack complexity, and high availability impact, potentially leading to a denial of service through an overflow panic. Currently, there is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion surrounding this vulnerability.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
< 0.24.4CPE matchmatch criteria | cpe:2.3:a:cloudflare:quiche:*:*:*:*:*:rust:*:* |
CVSS version used by this source: 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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