CVE-2020-10739Network attack vector

Proxy crash via premature Wasm callbacks

Published Jun 2, 2020 · Updated Aug 4, 2024

Null pointer dereference in Istio Envoy 1.4.0 through 1.4.8 and 1.5.0 through 1.5.3 allows remote attackers to crash proxies. Telemetry v2's Wasm Context invokes data, close, or lifecycle callbacks before the VM context has been created when crafted traffic reaches an ingress gateway or sidecar. Telemetry v2 must be enabled; it is not enabled by default in the 1.4.x branch, and exploitation interrupts the affected proxy's service.

CVSS severity7.5
High
EPSS probability2.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Null pointer dereference in Istio Envoy 1.4.0 through 1.4.8 and 1.5.0 through 1.5.3 allows remote attackers to crash proxies. Telemetry v2's Wasm Context invokes data, close, or lifecycle callbacks before the VM context has been created when crafted traffic reaches an ingress gateway or sidecar. Telemetry v2 must be enabled; it is not enabled by default in the 1.4.x branch, and exploitation interrupts the affected proxy's service.

The record

CVE
CVE-2020-10739
Published
Jun 2, 2020
Updated
Aug 4, 2024
Vendor
Istio
Product
Istio Envoy
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 2, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=>= 1.4.0, < 1.4.9
  2. Affected versionversion=>= 1.5.0, < 1.5.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Istio · Istio Envoyversion=>= 1.4.0, < 1.4.9; version=>= 1.5.0, < 1.5.4

Published CVSS scores

7.5Red Hat, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P

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-476NULL Pointer Dereference
T1499.004Application or System Exploitation

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

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Your stack

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