CVE-2023-5753

Adjacent memory corruption via unchecked HCI packet lengths

Published Oct 24, 2023 · Updated Feb 13, 2025

Buffer overflows in Zephyr RTOS before 3.5 allow physically proximate attackers to corrupt memory via malformed Bluetooth HCI packets. In hci_acl(), hci_event(), hci_event_prio(), and hci_iso(), assertion-only length checks disappear from non-assert builds before net_buf_pull_mem() removes headers from undersized buffers. Bluetooth host support and disabled assertions are required; successful triggering can crash the device or execute code if controller-supplied input crosses a security boundary.

CVSS severity6.3
Medium
EPSS probability0.87%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflows in Zephyr RTOS before 3.5 allow physically proximate attackers to corrupt memory via malformed Bluetooth HCI packets. In hci_acl(), hci_event(), hci_event_prio(), and hci_iso(), assertion-only length checks disappear from non-assert builds before net_buf_pull_mem() removes headers from undersized buffers. Bluetooth host support and disabled assertions are required; successful triggering can crash the device or execute code if controller-supplied input crosses a security boundary.

The record

CVE
CVE-2023-5753
Published
Oct 24, 2023
Updated
Feb 13, 2025
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
CWE-120, CWE-191, T1499.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 24, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record 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=* <3.5

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Zephyr Project · Zephyr RTOSversion=* <3.5

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
6.3Zephyr ProjectCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CWE-191Integer Underflow (Wrap or Wraparound)
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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