Kernel memory corruption via FunctionFS epfile race
Published Jul 16, 2024 · Updated Aug 5, 2026
Use-after-free in Linux kernel FunctionFS allows local users to corrupt kernel memory through concurrent endpoint teardown. During ffs_func_eps_disable, ffs_epfile_release can destroy ffs->epfiles and its read buffer before the first path acquires the spinlock, leaving a stale epfile pointer that frees the buffer again. The race requires local access to an active FunctionFS gadget during composition switching; a successful trigger causes a kernel crash or altered kernel execution.
Summary
What happened
Use-after-free in Linux kernel FunctionFS allows local users to corrupt kernel memory through concurrent endpoint teardown. During ffs_func_eps_disable, ffs_epfile_release can destroy ffs->epfiles and its read buffer before the first path acquires the spinlock, leaving a stale epfile pointer that frees the buffer again. The race requires local access to an active FunctionFS gadget during composition switching; a successful trigger causes a kernel crash or altered kernel execution.
The record
- CVE
- CVE-2022-48822
- Published
- Jul 16, 2024
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-416, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 16, 2024CVE 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
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=4.8.10 <4.9
- Affected versionversion=4.9
- Affected versionversion=5cd8f6788ff34999dbd4cbec81a6adfc215e1e60
- Affected versionversion=a9e6f83c2df199187a5248f824f31b6787ae23ae <0042178a69eb77a979e36a50dcce9794a3140ef8
- Affected versionversion=a9e6f83c2df199187a5248f824f31b6787ae23ae <32048f4be071f9a6966744243f1786f45bb22dc2
- Affected versionversion=a9e6f83c2df199187a5248f824f31b6787ae23ae <3e078b18753669615301d946297bafd69294ad2c
- Affected versionversion=a9e6f83c2df199187a5248f824f31b6787ae23ae <72a8aee863af099d4434314c4536d6c9a61dcf3c
- Affected versionversion=a9e6f83c2df199187a5248f824f31b6787ae23ae <c9fc422c9a43e3d58d246334a71f3390401781dc
- Affected versionversion=a9e6f83c2df199187a5248f824f31b6787ae23ae <cfe5f6fd335d882bcc829a1c8a7d462a455c626e
- Affected versionversion=a9e6f83c2df199187a5248f824f31b6787ae23ae <ebe2b1add1055b903e2acd86b290a85297edc0b3
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
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo