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VulnerabilityPublished Updated

CVE-2026-12236: zephyrproject zephyr · Dos

Affects zephyrproject zephyrSource CVE Database V5

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Not known to be exploited · CVSS 6.5 Medium : upgrade to 4.4.2 or 4.3.2 when convenient.

Data as of 11 Nov 2026, 23:24 UTC

CVSS 3.1 base score
6.5Medium
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (zephyr)CVSS 3.16.5
EPSS
0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 4.4.2, 4.3.2
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 13 Aug 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 11 Nov 2026.

What to do

Upgrade zephyrproject zephyr to 4.4.2 or 4.3.2.

Affected software

ProductAffectedFixed in
zephyrprojectzephyrAffected
  • >=4.4.0 <4.4.2
Fixed in
  • 4.4.2
zephyrprojectzephyrAffected
  • >=2.6.0 <4.3.2
Fixed in
  • 4.3.2
GitHubzephyrpkg:github/zephyrOther threatsAffected
  • >=2.6.0 <4.3.2
  • >=4.4.0 <4.4.2
Fixed in
  • 4.3.2
  • 4.4.2

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

AI-suggested

This vulnerability is fixed in Zephyr versions 4.3.2 and 4.4.2. Users should upgrade to these or later versions to remediate the issue. No additional mitigation is required as the fix properly validates the response length to prevent infinite loops.

Description

CVE-2026-12236 is a denial of service vulnerability in the Zephyr Bluetooth host GATT client. It occurs in the parse_read_std_char_desc() function when processing a malicious ATT Read By Type Response with a zero-length entry. This causes an infinite loop that hangs the Bluetooth host processing thread, leading to a denial of service. The flaw can be triggered by any connected peer during standard descriptor discovery without requiring authentication. The issue is fixed in Zephyr versions 4.3.2 and 4.4.2.

References

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