CVE-2026-48044 Envoy Zstd Decompressor: Ratio Check at Wrong Loop Depth lead to memory explosion
Attackers can cause memory exhaustion and denial of service in Envoy proxy by sending crafted zstd payloads when decompression is enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-48044?
CVE-2026-48044 is a high-severity denial of service vulnerability in Envoyproxy Envoy, published on 26 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.23.0 until 1.35.11, 1.36.7, 1.37.3, and 1.38.1, a vulnerability has been identified in Envoy's zstd decompressor implementation (ZstdDecompressorImpl). When zstd decompression is enabled, processing a specially crafted, highly compressed zstd payload can lead to massive memory allocation. An attacker can exploit this to cause severe memory exhaustion, potentially resulting in an Out-Of-Memory (OOM) kill and Denial of Service (DoS) for the Envoy proxy. This vulnerability is fixed in 1.35.11, 1.36.7, 1.37.3, and 1.38.1.
Weakness: CWE-409
Which versions are affected by CVE-2026-48044?
1 open source package ship an affected version, including envoy. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
envoy Bitnami | From 1.23.0 | 1.35.11, 1.36.7, 1.37.3, 1.38.1 |
Products include Envoyproxy Envoy.
How do I fix CVE-2026-48044?
Upgrade envoy to a fixed version for your release line: 1.35.11, 1.36.7, 1.37.3 or 1.38.1.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-48044 being exploited?
There is no known exploitation of CVE-2026-48044 in the wild and no public exploit code.
Other vulnerabilities in Envoyproxy Envoy
Sources
Also known as BIT-envoy-2026-48044, GHSA-m3p9-47wh-88wg.