Kernel memory corruption via oversized ext2 block size
Published Aug 25, 2026 · Updated Aug 25, 2026
Out-of-bounds write in the ext2 driver in Zephyr RTOS 3.5.0 through 4.4.1 allows physically proximate attackers to corrupt kernel memory. ext2_verify_disk_superblock() accepts an unbounded s_log_block_size, causing ext2_init_blocks_slab() to lay slab blocks beyond its fixed backing buffer before the first block read. A crafted ext2 image must be mounted on the device; the resulting supervisor-mode corruption can crash the system or enable code execution.
Summary
What happened
Out-of-bounds write in the ext2 driver in Zephyr RTOS 3.5.0 through 4.4.1 allows physically proximate attackers to corrupt kernel memory. ext2_verify_disk_superblock() accepts an unbounded s_log_block_size, causing ext2_init_blocks_slab() to lay slab blocks beyond its fixed backing buffer before the first block read. A crafted ext2 image must be mounted on the device; the resulting supervisor-mode corruption can crash the system or enable code execution.
The record
- CVE
- CVE-2026-13215
- Published
- Aug 25, 2026
- Updated
- Aug 25, 2026
- Vendor
- Zephyr Project
- Product
- Zephyr RTOS
- Classifications
- CWE-787, T1200
- Attack vector
- physical
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 25, 2026CVE publishedPublication date reported by the CVE source.
- Aug 25, 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?
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- Affected versionversion=3.5.0 <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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