CVE-2026-48042Public exploitNetwork attack vector

Proxy crash via recursive JSON object destruction

Published Jun 26, 2026 · Updated Jun 26, 2026

Denial of service in affected Envoy releases allows remote attackers to crash the proxy via deeply nested JSON input. Factory::loadFromString parses roughly 100,000 nested arrays successfully, but recursive destruction of the resulting Field object graph exhausts the process stack. Reachability requires a request path through a filter that calls loadFromString, including McpRouter or JsonToMetadata; the bounded result is an Envoy process crash.

CVSS severity7.5
High
EPSS probability0.56%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in affected Envoy releases allows remote attackers to crash the proxy via deeply nested JSON input. Factory::loadFromString parses roughly 100,000 nested arrays successfully, but recursive destruction of the resulting Field object graph exhausts the process stack. Reachability requires a request path through a filter that calls loadFromString, including McpRouter or JsonToMetadata; the bounded result is an Envoy process crash.

The record

CVE
CVE-2026-48042
Published
Jun 26, 2026
Updated
Jun 26, 2026
Vendor
Envoy Proxy
Product
Envoy
Classifications
CWE-1124, T1499.004
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=< 1.35.11
  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=< 1.35.11; 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 exploitPublished

Weakness, pattern, technique

CWE-1124Excessively Deep Nesting
T1499.004Application or System Exploitation

Public exploit references

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

Technologies

Your stack

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Your stack

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