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OpenAdvisories
High · 7.5 CVE-2026-48044 EUVD-2026-39820

Envoy Zstd Decompressor: Ratio Check at Wrong Loop Depth lead to memory explosion

Published Jun 26, 2026 · Updated Jun 26, 2026 · Assigned by GitHub_M

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.

Affected products

VendorProductAffectedFixed
envoyproxy envoy >= 1.38.0, < 1.38.1, >= 1.37.0, < 1.37.3, >= 1.36.0, < 1.36.7, >= 1.23.0, < 1.35.11 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
openSUSE Tumbleweed istioctl 1.30.2-1.1 openSUSE-SU-2026:11141-1

Advisories 2

References