CVE-2026-48044Network attack vector

OOM termination via late Zstd ratio check

Published Jun 26, 2026 · Updated Jun 26, 2026

Resource exhaustion in affected Envoy releases allows remote attackers to terminate the proxy by sending highly compressed Zstd data. ZstdDecompressorImpl checks MaxInflateRatio only after process() drains an entire input slice, while its inner loop appends every expanded chunk without enforcing the limit. The Zstd decompressor must be enabled and reachable; one crafted request can exhaust process memory, cause OOM termination, and interrupt all proxied traffic.

CVSS severity7.5
High
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Resource exhaustion in affected Envoy releases allows remote attackers to terminate the proxy by sending highly compressed Zstd data. ZstdDecompressorImpl checks MaxInflateRatio only after process() drains an entire input slice, while its inner loop appends every expanded chunk without enforcing the limit. The Zstd decompressor must be enabled and reachable; one crafted request can exhaust process memory, cause OOM termination, and interrupt all proxied traffic.

The record

CVE
CVE-2026-48044
Published
Jun 26, 2026
Updated
Jun 26, 2026
Vendor
Envoy Proxy
Product
Envoy
Classifications
CWE-409, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 26, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 1.23.0, < 1.35.11
  2. Affected versionversion=>= 1.36.0, < 1.36.7
  3. Affected versionversion=>= 1.37.0, < 1.37.3
  4. Affected versionversion=>= 1.38.0, < 1.38.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Envoy Proxy · Envoyversion=>= 1.23.0, < 1.35.11; version=>= 1.36.0, < 1.36.7; version=>= 1.37.0, < 1.37.3; version=>= 1.38.0, < 1.38.1

Published CVSS scores

7.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-409Improper Handling of Highly Compressed Data (Data Amplification)
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo