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VulnerabilityPublished

CVE-2026-87038: zephyrproject zephyr · Race

Affects zephyrproject zephyrSource CVE Database V5

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Not known to be exploited · CVSS 7.0 High : upgrade to 4.5.0 or 4.3.2 soon.

Data as of 4 Nov 2026, 06:28 UTC

CVSS 3.1 base score
7.0High
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (zephyr)CVSS 3.17.0
Patch
Available – fixed in 4.5.0, 4.3.2
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 4 Nov 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 3 Nov 2026.

What to do

Upgrade zephyrproject zephyr to 4.5.0 or 4.3.2.

Affected software

ProductAffectedFixed in
zephyrprojectzephyrAffected
  • >=4.4.0 <4.5.0
Fixed in
  • 4.5.0
zephyrprojectzephyrAffected
  • >=3.2.0 <4.3.2
Fixed in
  • 4.3.2
GitHubzephyrpkg:github/zephyrOther threatsAffected
  • >=3.2.0 <4.3.2
  • >=4.4.0 <4.5.0
Fixed in
  • 4.3.2
  • 4.5.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available in Zephyr versions 4.3.2 and 4.5.0. Users should upgrade to these or later versions to remediate the vulnerability. No additional mitigation steps are required beyond applying the official patch.

Description

CVE-2026-87038 is a race condition vulnerability in the Zephyr project's i3c_transfer() system call handler. The flaw arises because the user-supplied device descriptor is validated in place without snapshotting, allowing a race where a second thread can modify the bus field after validation but before use. This can lead to kernel-mode code execution from an unprivileged user thread, escaping the userspace memory-protection sandbox. The issue affects Zephyr versions from 3.2.0 up to but not including 4.3.2, and from 4.4.0 up to but not including 4.5.0. The vulnerability is fixed in versions 4.3.2 and 4.5.0 by copying and validating the descriptor in kernel space before use.

References

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