CVE-2025-4821 (GCVE-0-2025-4821)
Vulnerability from cvelistv5 – Published: 2025-06-18 15:47 – Updated: 2025-06-18 18:29
VLAI?
Title
Incorrect congestion window growth by invalid ACK ranges
Summary
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.
Severity ?
7.5 (High)
CWE
- CWE-770 - Allocation of Resources Without Limits or Throttling
Assigner
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Cloudflare | quiche |
Affected:
<0.24.4
|
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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