Kernel memory corruption via unchecked Xtensa relocation offset
Published Aug 12, 2026 · Updated Aug 12, 2026
Out-of-bounds write in Zephyr RTOS 3.7.0 through 4.4.1 allows local users to corrupt kernel memory via a crafted Xtensa LLEXT ELF. The relocatable PLT branch in llext_link_plt() adds an unchecked RELA r_offset to the target section address before an architecture-specific write. Exploitation requires CONFIG_LLEXT, writable attacker-influenced extension storage, and the Xtensa relocatable path; successful corruption can crash the device or alter privileged execution.
Summary
What happened
Out-of-bounds write in Zephyr RTOS 3.7.0 through 4.4.1 allows local users to corrupt kernel memory via a crafted Xtensa LLEXT ELF. The relocatable PLT branch in llext_link_plt() adds an unchecked RELA r_offset to the target section address before an architecture-specific write. Exploitation requires CONFIG_LLEXT, writable attacker-influenced extension storage, and the Xtensa relocatable path; successful corruption can crash the device or alter privileged execution.
The record
- CVE
- CVE-2026-12235
- Published
- Aug 12, 2026
- Updated
- Aug 12, 2026
- Vendor
- Zephyr Project
- Product
- Zephyr RTOS
- Classifications
- CWE-787, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 12, 2026CVE publishedPublication date reported by the CVE source.
- Aug 12, 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.
- Affected versionversion=3.7.0 <4.4.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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