Bug 2570673 (CVE-2026-12708)

Summary:	CVE-2026-12708 tokio-quiche: tokio-quiche: Denial of Service via unbounded memory consumption in HTTP/3 DATAGRAM handling
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability-draft	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	Keywords:	Security
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Hardware:	All
OS:	Linux
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Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in tokio-quiche. This vulnerability allows a remote peer to cause a Denial of Service (DoS) by exhausting process memory. When processing HTTP/3 DATAGRAM frames, the application creates and retains tracking state for every unique flow identifier received without enforcing limits. An attacker can transmit numerous distinct flow identifiers to force memory usage to grow without bound, resulting in an application crash. Both client and server implementations are affected when DATAGRAM handling is enabled.	Story Points:	---
Clone Of:		Environment:
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Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-11-10 20:14:45 UTC

Summary


Cloudflare tokio-quiche was found to contain an uncontrolled resource consumption vulnerability in its HTTP/3 DATAGRAM handling. For every previously unseen flow identifier (quarter stream ID) received in a DATAGRAM frame, tokio-quiche creates and retains new, per-flow state. A remote peer can send DATAGRAMs with many distinct identifiers, causing the per-connection flow map and associated channel state to grow without bound.

Impact


Exploitation can exhaust process memory and cause a denial of service. The vulnerable code is used in both client and server configurations, so either role can be affected by a malicious peer. QUIC DATAGRAM support in tokio-quiche is enabled by default through QuicSettings::enable_dgram; applications can disable it by setting this field to false. The vulnerable HTTP/3 path is reachable only when DATAGRAM support is negotiated with the peer. Core quiche and HTTP/3 deployments without DATAGRAM support are not affected. 






Mitigation


Disable DATAGRAMs in tokio-quiche’s QuicSettings::enable_dgram.






Remediation


Upgrade to tokio-quiche version 0.23.0 or later. The fixed code creates flow state only for valid DATAGRAM-capable request streams, which are bounded by QUIC’s stream limits. To tolerate packet reordering, servers retain early DATAGRAMs in a bounded, expiring buffer, while clients discard DATAGRAMs for unknown flows.