CVE-2025-71074functionfs: fix the open/removal races
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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In the Linux kernel, the following vulnerability has been resolved: functionfs: fix the open/removal races ffs_epfile_open() can race with removal, ending up with file->private_data pointing to freed object. There is a total count of opened files on functionfs (both ep0 and dynamic ones) and when it hits zero, dynamic files get removed. Unfortunately, that removal can happen while another thread is in ffs_epfile_open(), but has not incremented the count yet. In that case open will succeed, leaving us with UAF on any subsequent read() or write(). The root cause is that ffs->opened is misused; atomic_dec_and_test() vs. atomic_add_return() is not a good idea, when object remains visible all along. To untangle that * serialize openers on ffs->mutex (both for ep0 and for dynamic files) * have dynamic ones use atomic_inc_not_zero() and fail if we had zero ->opened; in that case the file we are opening is doomed. * have the inodes of dynamic files marked on removal (from the callback of simple_recursive_removal()) - clear ->i_private there. * have open of dynamic ones verify they hadn't been already removed, along with checking that state is FFS_ACTIVE.
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Modified
- Record last updated
- Oct 21, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from ddf8abd2599491cbad959c700b90ba72a5dce8d0 before 585a656283c954337036422afcd9cb70dd4135e7; from ddf8abd2599491cbad959c700b90ba72a5dce8d0 before 75240e5e51c6e6d67a3039384125fa54259a3926; from ddf8abd2599491cbad959c700b90ba72a5dce8d0 before e5bf5ee266633cb18fff6f98f0b7d59a62819eee | CNA record |
linux linux_kernel linux:linux_kernel | from 2.6.35.1 before 6.19; 2.6.35; 6.19; 6.19; 6.19; 6.19; 6.19; 6.19; and 2 more ranges | NVD |
References
- https://git.kernel.org/stable/c/585a656283c954337036422afcd9cb70dd4135e7
- https://git.kernel.org/stable/c/75240e5e51c6e6d67a3039384125fa54259a3926
- https://git.kernel.org/stable/c/e5bf5ee266633cb18fff6f98f0b7d59a62819eeepatch
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.