# CVE-2026-64496: iio: event: Fix event FIFO reset race > A race condition in the Linux kernel IIO event FIFO allows local attackers to leak adjacent kernel memory via out-of-bounds reads. - **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Local or same network only - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 25 Jul 2026 - **Updated:** 19 Oct 2026 - **Also known as:** ALSA-2026:52761, ALSA-2026:52765, AZL-93731, BELL-CVE-2026-64496, DEBIAN-CVE-2026-64496, GHSA-hh3r-jgc6-qr6q, RHSA-2026:52761, RHSA-2026:52765, RLSA-2026:52761, RLSA-2026:52765, ROOT-OS-DEBIAN-12-CVE-2026-64496, ROOT-OS-UBUNTU-2204-CVE-2026-64496, UBUNTU-CVE-2026-64496 ## What is CVE-2026-64496? CVE-2026-64496 is a high-severity vulnerability in Linux, published on 25 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim. ### Official 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. Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization) ## Which versions are affected by CVE-2026-64496? | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `bpftool` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel-abi-stablelists` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel-core` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel-cross-headers` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel-debug` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel-debug-core` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel-debug-devel` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel-debug-modules` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel-debug-modules-extra` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel-devel` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel-doc` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel-headers` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel-modules` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel-modules-extra` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel-rt` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.rt7.495.el8_10 | | `kernel-rt-core` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.rt7.495.el8_10 | | `kernel-rt-debug` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.rt7.495.el8_10 | | `kernel-rt-debug-core` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.rt7.495.el8_10 | | `kernel-rt-debug-devel` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.rt7.495.el8_10 | | `kernel-rt-debug-modules` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.rt7.495.el8_10 | | `kernel-rt-debug-modules-extra` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.rt7.495.el8_10 | | `kernel-rt-devel` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.rt7.495.el8_10 | | `kernel-rt-modules` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.rt7.495.el8_10 | | `kernel-rt-modules-extra` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.rt7.495.el8_10 | | `kernel-tools` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel-tools-libs` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel-tools-libs-devel` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel-zfcpdump` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel-zfcpdump-core` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel-zfcpdump-devel` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel-zfcpdump-modules` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `kernel-zfcpdump-modules-extra` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `perf` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `python3-perf` | AlmaLinux:8 | All versions | 4.18.0-553.154.1.el8_10 | | `bpftool` | Red Hat:enterprise_linux:8::baseos | All versions | 0:4.18.0-553.154.1.el8_10 | | `bpftool-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:4.18.0-553.154.1.el8_10 | | `kernel` | Red Hat:enterprise_linux:8::baseos | All versions | 0:4.18.0-553.154.1.el8_10 | | `kernel-abi-stablelists` | Red Hat:enterprise_linux:8::baseos | All versions | 0:4.18.0-553.154.1.el8_10 | | `kernel-core` | Red Hat:enterprise_linux:8::baseos | All versions | 0:4.18.0-553.154.1.el8_10 | ## How do I fix CVE-2026-64496? Apply the vendor's patch. ## Is CVE-2026-64496 being exploited? There is no known exploitation of CVE-2026-64496 in the wild and no public exploit code. ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-64496 and fix it if it is affected. What it is: CVE-2026-64496 is a high-severity vulnerability in Linux, published on 25 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-64496 in the wild and no public exploit code. Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-64496/ (Markdown: https://insights.sbomify.com/CVE-2026-64496/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64496 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64496 - OSV: https://osv.dev/vulnerability/CVE-2026-64496 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-64496/ Summaries are generated and may contain mistakes; the official description above is the record.