Quick answers
- Is This vulnerability exploited in the wild?
- No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.
- How severe is This vulnerability?
- Informational severity, published 29 June 2026.
- Which products and versions are affected?
- Envoy Proxy <unknown>.
- Is there a fix for This vulnerability?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is This vulnerability attacked?
- It is attacked over the network, in a software library.
- Am I affected?
- Check whether you run Envoy Proxy or Google Cloud Platform 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.
Technical details
A vulnerability in Envoy Proxy's QPACK (QUIC Package Compression) decoder allows a network-based attacker to cause a denial-of-service condition in the HTTP/3 stack. The flaw occurs when the decoder encounters blocked QPACK streams, which can be triggered by specially crafted HTTP/3 requests. The vulnerability is reachable over the network from any client capable of sending HTTP/3 traffic to an affected Envoy instance; no authentication is required. Successful exploitation causes the HTTP/3 connection handler to fail, rendering the proxy unable to process legitimate traffic. Patches are available through Google Cloud Service Mesh updates.
Affected products
- Envoy Envoy Proxy <unknown>
Timeline
- 2026-06-29: disclosed