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Response snapshot Nov 3, 2026, 20:56 UTC

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VulnerabilityCVE-2026-64496

Linux kernel: iio: event: Fix event FIFO reset race

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.

At a glance

Exploited
Not known
Severity
7.1 High (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-64496 (opens a new tab)

What happened

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.

Continue reading

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.

Scores and how they were measured

CVSS base severity

7.1

Version 3.1As of

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    NVD CVE-2026-64496 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  4. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, November 3). Linux kernel: iio: event: Fix event FIFO reset race (CVE-2026-64496). https://kevwire.com/record/CVE-2026-64496

MLA

"Linux kernel: iio: event: Fix event FIFO reset race (CVE-2026-64496)." KEVWire, 3 Nov. 2026, kevwire.com/record/CVE-2026-64496.

Chicago

KEVWire. "Linux kernel: iio: event: Fix event FIFO reset race (CVE-2026-64496)." Last modified November 3, 2026. https://kevwire.com/record/CVE-2026-64496.

Evidence summary (plain text)

Linux kernel: iio: event: Fix event FIFO reset race (Jul 25, 2026).
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.
CVSS 7.1 (version 3.1; evidence as of Nov 3, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-64496).
Sources:
NVD CVE-2026-64496: https://nvd.nist.gov/vuln/detail/CVE-2026-64496
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-03T18:06:04.789Z&lastModEndDate=2026-11-03T19:40:57.574Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-03T17:35:57.416Z&lastModEndDate=2026-11-03T19:05:57.748Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-03T17:01:00.112Z&lastModEndDate=2026-11-03T18:35:55.788Z&resultsPerPage=500&startIndex=0
Record ID: CVE-2026-64496.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Nov 3, 2026, 19:40 UTC. Ingestion is not an independent editorial investigation.

NVD status: Awaiting Analysis. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

Record detail