Kernel memory corruption via FunctionFS use-after-free
Published Mar 27, 2025 · Updated Aug 5, 2026
Use-after-free in Linux kernel FunctionFS 2.6.35 through 6.1.8 allows local users to corrupt kernel memory during a fast composition switch. ffs_ep0_queue_wait retains ep0req while functionfs_unbind can free it and set it to NULL without serialization, so a concurrent endpoint-zero read or write dereferences freed memory. Exploitation requires local low-privileged access and a FunctionFS gadget undergoing a rapid composition change, with resulting compromise of kernel confidentiality, integrity, and availability.
Summary
What happened
Use-after-free in Linux kernel FunctionFS 2.6.35 through 6.1.8 allows local users to corrupt kernel memory during a fast composition switch. ffs_ep0_queue_wait retains ep0req while functionfs_unbind can free it and set it to NULL without serialization, so a concurrent endpoint-zero read or write dereferences freed memory. Exploitation requires local low-privileged access and a FunctionFS gadget undergoing a rapid composition change, with resulting compromise of kernel confidentiality, integrity, and availability.
The record
- CVE
- CVE-2022-49755
- Published
- Mar 27, 2025
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-416, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 27, 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=2.6.35
- Affected versionversion=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <6a19da111057f69214b97c62fb0ac59023970850
- Affected versionversion=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <6aee197b7fbcd61596a78b47d553f2f99111f217
- Affected versionversion=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <6dd9ea05534f323668db94fcc2726c7a84547e78
- Affected versionversion=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <a8d40942df074f4ebcb9bd3413596d92f323b064
- Affected versionversion=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <ae8e136bcaae96163b5821984de1036efc9abb1a
- Affected versionversion=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <e9036e951f93fb8d7b5e9d6e2c7f94a4da312ae4
- Affected versionversion=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <facf353c9e8d7885b686d9a4b173d4e0af6441d2
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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