CVE-2026-11985

Cross-thread data disclosure via unpreserved FPU registers

Published Aug 11, 2026 · Updated Aug 11, 2026

Information disclosure in Zephyr Project Zephyr RTOS 1.13.0 through 4.4.1 allows local users to read cross-thread ARM FPU register state. When CONFIG_FPU enables either floating-point ABI without CONFIG_FPU_SHARING, context switches leave callee-saved s16-s31 registers unpreserved even though the compiler can emit floating-point instructions in every thread. Exploitation requires CONFIG_USERSPACE, hardware FPU use, and a co-resident unprivileged thread; disclosure is opportunistic and limited to 16 registers, while non-userspace builds suffer cross-thread state corruption.

CVSS severity3.6
Low
EPSS probability0.09%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Zephyr Project Zephyr RTOS 1.13.0 through 4.4.1 allows local users to read cross-thread ARM FPU register state. When CONFIG_FPU enables either floating-point ABI without CONFIG_FPU_SHARING, context switches leave callee-saved s16-s31 registers unpreserved even though the compiler can emit floating-point instructions in every thread. Exploitation requires CONFIG_USERSPACE, hardware FPU use, and a co-resident unprivileged thread; disclosure is opportunistic and limited to 16 registers, while non-userspace builds suffer cross-thread state corruption.

The record

CVE
CVE-2026-11985
Published
Aug 11, 2026
Updated
Aug 11, 2026
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
CWE-200
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Aug 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 11, 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=1.13.0 <=4.4.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

Zephyr Project · Zephyr RTOSversion=1.13.0 <=4.4.1

Published CVSS scores

3.6GitHub / Zephyr ProjectCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-200Exposure of Sensitive Information to an Unauthorized Actor

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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