CVE-2026-1681Public exploit

Device crash via recursive loopback packet processing

Published May 12, 2026 · Updated May 12, 2026

Uncontrolled recursion in Zephyr RTOS 4.3 and earlier allows local users to crash a device by pinging its own IPv4 address. The net ping shell command processes a loopback echo request and its reply inline on the same system work-queue stack before prior frames return. Reachability requires access to the device shell and an enabled network shell; the nested input frames exhaust the work-queue stack and halt the system.

CVSS severity6.1
Medium
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled recursion in Zephyr RTOS 4.3 and earlier allows local users to crash a device by pinging its own IPv4 address. The net ping shell command processes a loopback echo request and its reply inline on the same system work-queue stack before prior frames return. Reachability requires access to the device shell and an enabled network shell; the nested input frames exhaust the work-queue stack and halt the system.

The record

CVE
CVE-2026-1681
Published
May 12, 2026
Updated
May 12, 2026
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
CWE-674, CAPEC-230, CAPEC-231, T1499
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 12, 2026CVE publishedPublication date reported by the CVE source.
  2. May 12, 2026Record 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=* <=4.3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Zephyr Project · Zephyr RTOSversion=* <=4.3

Published CVSS scores

6.1Zephyr ProjectCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/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.

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No observations available

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

Weakness, pattern, technique

CWE-674Uncontrolled Recursion
CAPEC-230Serialized Data with Nested Payloads
CAPEC-231Oversized Serialized Data Payloads
T1499Endpoint Denial of Service

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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