CVE-2025-4821

Description

Impact Cloudflare quiche was discovered to be vulnerable to incorrect congestion window growth, which could cause it to send data at a rate faster than the path might actually support. An unauthenticated remote attacker can exploit the vulnerability by first completing a handshake and initiating a congestion-controlled data transfer towards itself. Then, it could manipulate the victim's congestion control state by sending ACK frames covering a large range of packet numbers (including packet numbers that had never been sent); see RFC 9000 Section 19.3. The victim could grow the congestion window beyond typical expectations and allow more bytes in flight than the path might really support. In extreme cases, the window might grow beyond the limit of the internal variable's type, leading to an overflow panic. Patches quiche 0.24.4 is the earliest version containing the fix for this issue.

Reserved 2025-05-16 | Published 2025-06-18 | Updated 2025-06-18 | Assigner cloudflare

Problem types

CWE-770 Allocation of Resources Without Limits or Throttling

Product status

Default status
unaffected

<0.24.4
affected

References

github.com/...quiche/security/advisories/GHSA-6m38-4r9r-5c4m

cve.org (CVE-2025-4821)

nvd.nist.gov (CVE-2025-4821)

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