CVE-2026-9263Public exploit

Controller-memory disclosure via ISO length underflow

Published Jun 30, 2026 · Updated Jun 30, 2026

Out-of-bounds read in Zephyr RTOS 3.3.0 through 4.4.1 allows physically proximate attackers to disclose memory via Bluetooth ISO. The ISOAL framed receive path accepts start-segment lengths below three, underflows an 8-bit subtraction, and copies up to 255 bytes beyond the PDU into a host HCI ISO packet. Reachability requires Controller ISO support, framed CIS or BIS reception, and the Controller-to-Host path; the bounded consequence is adjacent controller-memory disclosure.

CVSS severity6.5
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in Zephyr RTOS 3.3.0 through 4.4.1 allows physically proximate attackers to disclose memory via Bluetooth ISO. The ISOAL framed receive path accepts start-segment lengths below three, underflows an 8-bit subtraction, and copies up to 255 bytes beyond the PDU into a host HCI ISO packet. Reachability requires Controller ISO support, framed CIS or BIS reception, and the Controller-to-Host path; the bounded consequence is adjacent controller-memory disclosure.

The record

CVE
CVE-2026-9263
Published
Jun 30, 2026
Updated
Jun 30, 2026
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
CWE-125
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 30, 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=3.3.0 <4.5.0

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Zephyr Project · Zephyr RTOSversion=3.3.0 <4.5.0

Published CVSS scores

8.1NIST NVDCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
6.5Zephyr ProjectCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

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-125Out-of-bounds Read

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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