Local system crash via FunctionFS endpoint race
Published Dec 8, 2025 · Updated May 23, 2026
A race condition in Linux kernel FunctionFS allows local users to crash the system through concurrent endpoint enable and data reset operations. ffs_data_clear() sets ffs->epfiles to NULL before clearing eps_count, so ffs_func_eps_enable() dereferences epfile->ep after usb_ep_enable() succeeds. Local low-privileged access to a configured USB FunctionFS gadget is required, and the demonstrated consequence is a kernel crash.
Summary
What happened
A race condition in Linux kernel FunctionFS allows local users to crash the system through concurrent endpoint enable and data reset operations. ffs_data_clear() sets ffs->epfiles to NULL before clearing eps_count, so ffs_func_eps_enable() dereferences epfile->ep after usb_ep_enable() succeeds. Local low-privileged access to a configured USB FunctionFS gadget is required, and the demonstrated consequence is a kernel crash.
The record
- CVE
- CVE-2025-40315
- Published
- Dec 8, 2025
- Updated
- May 23, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Dec 8, 2025CVE publishedPublication date reported by the CVE source.
- May 23, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0042178a69eb77a979e36a50dcce9794a3140ef8 <1c0dbd240be3f87cac321b14e17979b7e9cb6a8f
- Affected versionversion=32048f4be071f9a6966744243f1786f45bb22dc2
- Affected versionversion=3e078b18753669615301d946297bafd69294ad2c
- Affected versionversion=4.14.267 <4.15
- Affected versionversion=4.19.230 <4.20
- Affected versionversion=5.10.101 <5.10.247
- Affected versionversion=5.15.24 <5.15.197
- Affected versionversion=5.16.10 <5.17
- Affected versionversion=5.17
- Affected versionversion=5.4.180 <5.4.302
- Affected versionversion=72a8aee863af099d4434314c4536d6c9a61dcf3c <9ec40fba7357df2d36f4c2e2f3b9b1a4fba0a272
- Affected versionversion=c9fc422c9a43e3d58d246334a71f3390401781dc <b00d2572c16e8e59e979960d3383c2ae9cebd195
- Affected versionversion=cfe5f6fd335d882bcc829a1c8a7d462a455c626e
- Affected versionversion=ebe2b1add1055b903e2acd86b290a85297edc0b3 <30880e9df27332403dd638a82c27921134b3630b
- Affected versionversion=ebe2b1add1055b903e2acd86b290a85297edc0b3 <c53e90563bc148e4e0ad09fe130ba2246d426ea6
- Affected versionversion=ebe2b1add1055b903e2acd86b290a85297edc0b3 <cfd6f1a7b42f62523c96d9703ef32b0dbc495ba4
- Affected versionversion=ebe2b1add1055b903e2acd86b290a85297edc0b3 <d62b808d5c68a931ad0849a00a5e3be3dd7e0019
- Affected versionversion=ebe2b1add1055b903e2acd86b290a85297edc0b3 <fc1141a530dfc91f0ee19b7f422a2d24829584bc
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What is affected?
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Attacks
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