CVE-2026-48044: Envoy Zstd Decompressor: Ratio Check at Wrong Loop Depth lead to memory explosion
Vulnerability summary
CVE-2026-48044 is a high (CVSS 7.5) vulnerability in envoyproxy envoy. EPSS estimates a 0.49% chance of exploitation in the next 30 days, higher than 40.9% of scored vulnerabilities. 1 public exploit is recorded.
Advisory lineage
Upstream 0 · Downstream 1 · Related 1Timeline
- 26-06-2026PublishedVulnerability first disclosed.
- 26-06-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
2 scores · 2 sources · 1 version- NVDNIST7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.49%
Chance of exploitation in the next 30 days
Percentile
41%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.49% on 22-09-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
1 foundEnvoy
Maturity: poc
Weaknesses
CWE · root causeAffected systems
Envoyproxy1 product
- 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 | ≥ 1.23.0, < 1.35.13 | ≥ 1.36.0, < 1.36.9 | ≥ 1.37.0, < 1.37.5 | ≥ 1.38.0, < 1.38.3
1 vendor · 1 product
References
1 links- github.com/envoyproxy/envoy/security/advisories/GHSA-m3p9-47wh-88wgX Refsource CONFIRMMitigationVendor AdvisoryExploit