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VulnerabilityPublished

CVE-2026-85034: zephyrproject zephyr · Bounds

Affects zephyrproject zephyrSource CVE Database V5

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Not known to be exploited · CVSS 6.7 Medium : upgrade to 4.5.0 or 4.3.2 when convenient.

Data as of 3 Nov 2026, 13:58 UTC

CVSS 3.1 base score
6.7Medium
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (zephyr)CVSS 3.16.7
Patch
Available – fixed in 4.5.0, 4.3.2
CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 3 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
  • >=3.4.0 <4.3.2
Fixed in
  • 4.3.2
GitHubzephyrpkg:github/zephyrOther threatsAffected
  • >=3.4.0 <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

The vulnerability is fixed in Zephyr versions 4.3.2 and 4.5.0. Users should upgrade to these or later versions to ensure the fix rejecting oversized notifications and indications is applied. No additional mitigations are required as the fix prevents delivery of oversized values to subscribers.

Description

CVE-2026-85034 is a vulnerability in the Zephyr Bluetooth host GATT client where notifications or indications with values exceeding the Bluetooth specification limit of 512 octets can cause a buffer overflow. This occurs because the code does not enforce the negotiated ATT MTU or the maximum attribute length, allowing oversized values to overwrite adjacent memory structures. The flaw can be triggered by a malicious or compromised GATT server sending oversized notifications or indications. The issue is fixed in Zephyr versions 4.3.2 and 4.5.0 by rejecting oversized values before subscriber callbacks are invoked.

References

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