Kernel disclosure via uninitialized Comedi instruction buffer
Published Jul 28, 2025 · Updated Aug 5, 2026
Uninitialized memory use in Linux Comedi allows local users to read kernel data and corrupt device state through local ioctls. The do_insn_ioctl() and do_insnlist_ioctl() paths copy only insn->n elements into a 16-element buffer, leaving later elements uninitialized for handlers that read them. Access requires an open /dev/comediN device; crafted instructions can expose kernel slab data, alter driver or hardware state, or interrupt service.
Summary
What happened
Uninitialized memory use in Linux Comedi allows local users to read kernel data and corrupt device state through local ioctls. The do_insn_ioctl() and do_insnlist_ioctl() paths copy only insn->n elements into a 16-element buffer, leaving later elements uninitialized for handlers that read them. Access requires an open /dev/comediN device; crafted instructions can expose kernel slab data, alter driver or hardware state, or interrupt service.
The record
- CVE
- CVE-2025-38478
- Published
- Jul 28, 2025
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-908
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 28, 2025CVE publishedPublication date reported by the CVE source.
- Aug 5, 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=2.6.29
- Affected versionversion=ed9eccbe8970f6eedc1b978c157caf1251a896d4 <020eed5681d0f9bced73970368078a92d6cfaa9c
- Affected versionversion=ed9eccbe8970f6eedc1b978c157caf1251a896d4 <13e4d9038a1e869445a996a3f604a84ef52fe8f4
- Affected versionversion=ed9eccbe8970f6eedc1b978c157caf1251a896d4 <46d8c744136ce2454aa4c35c138cc06817f92b8e
- Affected versionversion=ed9eccbe8970f6eedc1b978c157caf1251a896d4 <673ee92bd2d31055bca98a1d96b653f5284289c4
- Affected versionversion=ed9eccbe8970f6eedc1b978c157caf1251a896d4 <6f38c6380c3b38a05032b8881e41137385a6ce02
- Affected versionversion=ed9eccbe8970f6eedc1b978c157caf1251a896d4 <c42116dc70af6664526f7aa82cf937824ab42649
- Affected versionversion=ed9eccbe8970f6eedc1b978c157caf1251a896d4 <d3436638738ace8f101af7bdee2eae1bc38e9b29
- Affected versionversion=ed9eccbe8970f6eedc1b978c157caf1251a896d4 <fe8713fb4e4e82a4f91910d9a41bf0613e69a0b9
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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