CVE-2023-5563Public exploit

Device halt via IRQ-context sleep during bus-off

Published Oct 12, 2023 · Updated Sep 17, 2024

Denial of service in Zephyr RTOS 3.3 through 3.4 allows remote attackers on the CAN bus to halt devices by inducing an SJA1000 bus-off event. The can_sja1000_handle_error_warning_irq() handler calls can_sja1000_leave_reset_mode(), whose register-polling loop invokes k_sleep() while still in interrupt context. Exposure requires the SJA1000 backend and CONFIG_CAN_AUTO_BUS_OFF_RECOVERY=y; the resulting fatal exception halts the device.

CVSS severity7.1
High
EPSS probability0.45%
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 Zephyr RTOS 3.3 through 3.4 allows remote attackers on the CAN bus to halt devices by inducing an SJA1000 bus-off event. The can_sja1000_handle_error_warning_irq() handler calls can_sja1000_leave_reset_mode(), whose register-polling loop invokes k_sleep() while still in interrupt context. Exposure requires the SJA1000 backend and CONFIG_CAN_AUTO_BUS_OFF_RECOVERY=y; the resulting fatal exception halts the device.

The record

CVE
CVE-2023-5563
Published
Oct 12, 2023
Updated
Sep 17, 2024
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
CWE-703, T1499
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 12, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 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=3.3 <=3.4

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Zephyr Project · Zephyr RTOSversion=3.3 <=3.4

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.1Zephyr ProjectCVSS:3.1/AV:A/AC:L/PR:N/UI:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-703Improper Check or Handling of Exceptional Conditions
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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