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

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.

Scores

EPSS (exploitation in 30 days)

0.49% · top 58% of all CVEs (4 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: yes · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.

Weakness

• CWE-409: Improper Handling of Highly Compressed Data (Data Amplification) (opens in a new tab)All about CWE-409 and its CVEs

Affected products

• envoyproxy · envoy

  • affected >= 1.38.0, < 1.38.1
  • affected >= 1.37.0, < 1.37.3
  • affected >= 1.36.0, < 1.36.7
  • affected >= 1.23.0, < 1.35.11

References (1)

• https://github.com/envoyproxy/envoy/security/advisories/GHSA-m3p9-47wh-88wg (opens in a new tab)x_refsource_CONFIRM

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-48044](https://trackcve.app/badge/CVE-2026-48044.svg)](https://trackcve.app/cve/CVE-2026-48044)

Record last updated 26 Jun 2026, 18:31 UTC.