# CVE-2026-99173: linux: In the Linux kernel, the following vulnerability has been resolved:  eventfs: Free the eventfs_inode after an rcu gra...

CVE-2026-99173 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-99173, released November 3, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-99173
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0013
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 28, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  eventfs: Free the eventfs_inode after an rcu grace period too  tracefs_d_revalidate() reads ->is_freed of the eventfs_inode that dentry->d_fsdata points to, and ->d_revalidate() is called in rcu pathwalk mode with nothing but rcu_read_lock() held. The dentry itself stays around for such a walker, but tracefs_d_release() drops its reference to the eventfs_inode when the dentry is killed, and release_ei() then frees it after a grace period of eventfs_srcu. An SRCU grace period doesn't wait for rcu_read_lock() sections, so the walker can read an eventfs_inode that is already gone.  With a pathwalk held up in tracefs_d_revalidate() while the dentry goes away:    BUG: KASAN: slab-use-after-free in tracefs_d_revalidate+0x76/0x90   Read of size 1 at addr ff1100010152d8d0 by task walker/97   Call Trace:    <TASK>    tracefs_d_revalidate+0x76/0x90    lookup_fast+0x320/0x640    path_lookupat+0x160/0xb00    filename_lookup+0x1f1/0x5b0    vfs_statx+0xd7/0x3b0    vfs_fstatat+0x4d/0x90    __do_sys_newfstatat+0xa0/0x100    do_syscall_64+0x10e/0x5e0    entry_SYSCALL_64_after_hwframe+0x77/0x7f   [...]   Allocated by task 1:    __kmalloc_cache_noprof+0x249/0x560    eventfs_create_dir+0x7a/0x590    event_create_dir+0x2fb/0xcf0    trace_add_event_call+0xbf/0x150   [...]   Freed by task 11:    kfree+0x1db/0x5b0    srcu_invoke_callbacks+0x3a3/0x620    process_one_work+0x937/0x1810    worker_thread+0x4f1/0xd60  Before commit 8e556432477e ("eventfs: Use SRCU for freeing eventfs_inodes") release_ei() used call_rcu(), which covered the walker, while eventfs_iterate() needs the SRCU grace period. Wait for both and chain call_rcu() from the SRCU callback.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.115-2 | [DEBIAN-CVE-2026-99173](https://patchblox.com/security/data/fix/linux/debian-cve-2026-99173.md) | Nov 3, 2026 |
| Linux | linux Debian 14 | 7.2.13-1 | [DEBIAN-CVE-2026-99173](https://patchblox.com/security/data/fix/linux/debian-cve-2026-99173.md) | Nov 3, 2026 |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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