CVE-2026-64496
HIGHCVE-2026-64496 is a high-severity (CVSS 7.1) vulnerability in Kernel. O3 Security confirms whether CVE-2026-64496 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
iio: event: Fix event FIFO reset race
Blast Radius
KernelReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Linux packages — download data is not available via public APIs for these ecosystems.
Description
In the Linux kernel, the following vulnerability has been resolved:
iio: event: Fix event FIFO reset race
iio_event_getfd() creates the event file descriptor with
anon_inode_getfd(), which allocates a new fd, creates the anonymous
file and installs it in the process fd table before returning to the
caller.
The IIO code resets the event FIFO after anon_inode_getfd() has returned,
but before IIO_GET_EVENT_FD_IOCTL has copied the fd number to userspace.
But since fd tables are shared between threads, another thread can guess
the newly allocated fd number and issue a read() on it as soon as the fd
has been installed.
This means the kfifo_to_user() in iio_event_chrdev_read() can run in
parallel with the kfifo_reset_out() in iio_event_getfd().
The kfifo documentation says that kfifo_reset_out() is only safe when it
is called from the reader thread and there is only one concurrent reader.
Otherwise it is dangerous and must be handled in the same way as
kfifo_reset().
If that happens, kfifo_to_user() can advance the FIFO out index based
on state from before the reset, after the reset has already moved the out
index to the current in index. That can leave the FIFO with an out
index past the in index. A later read() can then see an underflowed
FIFO length and copy more data than the event FIFO buffer contains. This
can result in an out-of-bounds read and leak adjacent kernel memory to
userspace.
Move the FIFO reset before anon_inode_getfd(). At that point the event fd is
marked busy, but the new fd has not been installed yet, so userspace cannot
access it while the FIFO is reset.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐧Linux | Kernel | ≥ 3.15.0&&< 5.10.261 | 5.10.261 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Kernel. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update Kernel to 5.10.261 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-64496 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-64496 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-64496. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-64496 in your dependencies?
O3 detects CVE-2026-64496 across Linux dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.