Is CVE-2026-12708 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-12708 being exploited in the wild.

How severe is CVE-2026-12708?

Informational severity, published 10 November 2026.

Which products and versions are affected?

Cloudflare Tokio-Quiche <= 0.20.1.

How is CVE-2026-12708 attacked?

It is attacked over the network.

Am I affected by CVE-2026-12708?

Check whether you run Cloudflare Tokio-Quiche at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-12708: Cloudflare tokio-quiche uncontrolled resource consumption in HTTP/3 DATAGRAM

Q: Is there a fix for CVE-2026-12708?

Yes: fixed in tokio-quiche 0.23.0. Until then: Disable DATAGRAM support by setting QuicSettings::enable_dgram to false in tokio-quiche configuration until an upgrade to version 0.23.0 or later is possible. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-12708 attacked?

It is attacked over the network.

Q: Am I affected by CVE-2026-12708?

Check whether you run Cloudflare Tokio-Quiche at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-12708 · Severity: info · Published 2026-11-10

Cloudflare's tokio-quiche is a QUIC protocol library used in network communication. A flaw in its HTTP/3 DATAGRAM handling allows remote attackers to exhaust server or client memory by sending crafted packets with many distinct identifiers, causing a denial-of-service outage. The vulnerability affects both client and server deployments when DATAGRAM support is enabled.

Vendors: Cloudflare.

Quick answers

Is CVE-2026-12708 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-12708 being exploited in the wild.
How severe is CVE-2026-12708?: Informational severity, published 10 November 2026.
Which products and versions are affected?: Cloudflare Tokio-Quiche <= 0.20.1.
Is there a fix for CVE-2026-12708?: Yes: fixed in tokio-quiche 0.23.0. Until then: Disable DATAGRAM support by setting QuicSettings::enable_dgram to false in tokio-quiche configuration until an upgrade to version 0.23.0 or later is possible. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-12708 attacked?: It is attacked over the network.
Am I affected by CVE-2026-12708?: Check whether you run Cloudflare Tokio-Quiche at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

Fixed in: tokio-quiche 0.23.0

Disable DATAGRAM support by setting QuicSettings::enable_dgram to false in tokio-quiche configuration until an upgrade to version 0.23.0 or later is possible.

Technical details

An uncontrolled resource consumption vulnerability exists in tokio-quiche's HTTP/3 DATAGRAM frame handling: for each previously unseen flow identifier (quarter stream ID), the library creates unbounded per-flow state entries that are never cleaned up, allowing a remote peer to exhaust process memory. The vulnerable code path requires DATAGRAM support to be negotiated and enabled via QuicSettings::enable_dgram. The fix in version 0.23.0 bounds flow state creation to valid DATAGRAM-capable request streams and implements an expiring buffer for early arrivals.

Affected products

Cloudflare tokio-quiche <= 0.20.1

Timeline

2026-11-10: disclosed

References

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