Vulnerability · Published Jan 20, 2025 · Assigned by Linux
CVE-2025-21655io_uring/eventfd: ensure io_eventfd_signal() defers another RCU period
High 7.8
In plain English
A high-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 17% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)7.8High
Exploit odds (30 days)0.3%top 83.1% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known
Official description
In the Linux kernel, the following vulnerability has been resolved: io_uring/eventfd: ensure io_eventfd_signal() defers another RCU period io_eventfd_do_signal() is invoked from an RCU callback, but when dropping the reference to the io_ev_fd, it calls io_eventfd_free() directly if the refcount drops to zero. This isn't correct, as any potential freeing of the io_ev_fd should be deferred another RCU grace period. Just call io_eventfd_put() rather than open-code the dec-and-test and free, which will correctly defer it another RCU grace period.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | kernel | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-64k | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-64k-core | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-64k-debug | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-64k-debug-core | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-64k-debug-devel | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-64k-debug-devel-matched | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-64k-debug-modules | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-64k-debug-modules-core | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-64k-debug-modules-extra | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-64k-devel | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-64k-devel-matched | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-64k-modules | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-64k-modules-core | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-64k-modules-extra | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-abi-stablelists | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-core | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-cross-headers | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-debug | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-debug-core | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-debug-devel | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-debug-devel-matched | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-debug-modules | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-debug-modules-core | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-debug-modules-extra | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-debug-uki-virt | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-devel | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-devel-matched | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-doc | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-headers | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-modules | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-modules-core | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-modules-extra | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-modules-extra-matched | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-64k | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-64k-core | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-64k-debug | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-64k-debug-core | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-64k-debug-devel | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-64k-debug-modules | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-64k-debug-modules-core | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-64k-debug-modules-extra | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-64k-devel | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-64k-modules | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-64k-modules-core | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-64k-modules-extra | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-core | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-debug | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-debug-core | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-debug-devel | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-debug-modules | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-debug-modules-core | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-debug-modules-extra | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-devel | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-modules | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-modules-core | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-rt-modules-extra | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-tools | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-tools-libs | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-tools-libs-devel | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-uki-virt | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-uki-virt-addons | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-zfcpdump | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-zfcpdump-core | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-zfcpdump-devel | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-zfcpdump-devel-matched | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-zfcpdump-modules | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-zfcpdump-modules-core | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | kernel-zfcpdump-modules-extra | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | libperf | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | perf | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | python3-perf | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | rtla | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| AlmaLinux:10 | rv | 6.12.0-124.8.1.el10_1 | ALSA-2025:20095 |
| Debian:12 | linux | 6.1.128-1 | DEBIAN-CVE-2025-21655 |
| Debian:12 | linux | 6.1.128-1 | DSA-5860-1 |
| Debian:13 | linux | 6.12.10-1 | DEBIAN-CVE-2025-21655 |
| Debian:14 | linux | 6.12.10-1 | DEBIAN-CVE-2025-21655 |
| Rocky Linux:10 | kernel | 0:6.12.0-124.8.1.el10_1 | RLSA-2025:20095 |
| Ubuntu:24.04:LTS | linux | 6.8.0-60.63 | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-allwinner-5.19 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-aws | 6.8.0-1029.31 | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-aws-5.19 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-aws-6.2 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-aws-6.5 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-aws-6.8 | 6.8.0-1029.31~22.04.1 | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-azure | 6.8.0-1029.34 | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-azure-5.19 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-azure-6.11 | 6.11.0-1012.12~24.04.1 | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-azure-6.2 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-azure-6.5 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-azure-6.8 | 6.8.0-1029.34~22.04.1 | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-azure-fde-5.19 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-azure-fde-6.2 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-azure-nvidia | 6.8.0-1016.17 | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-gcp | 6.8.0-1030.32 | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-gcp-5.19 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-gcp-6.11 | 6.11.0-1011.11~24.04.1 | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-gcp-6.2 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-gcp-6.5 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-gcp-6.8 | 6.8.0-1030.32~22.04.1 | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-gke | 6.8.0-1025.29 | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-gkeop | 6.8.0-1012.14 | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-hwe-5.19 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-hwe-6.11 | 6.11.0-21.21~24.04.1 | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-hwe-6.2 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-hwe-6.5 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-hwe-6.8 | 6.8.0-60.63~22.04.1 | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-ibm | 6.8.0-1026.26 | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-ibm-6.8 | 6.8.0-1026.26~22.04.1 | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-intel-iot-realtime | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-lowlatency | 6.8.0-60.63.1 | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-lowlatency-hwe-5.19 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-lowlatency-hwe-6.2 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-lowlatency-hwe-6.5 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-lowlatency-hwe-6.8 | 6.8.0-60.63.1~22.04.1 | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-nvidia | 6.8.0-1028.31 | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-nvidia-6.11 | 6.11.0-1007.7 | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-nvidia-6.2 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-nvidia-6.5 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-nvidia-6.8 | 6.8.0-1028.31~22.04.1 | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-nvidia-lowlatency | 6.8.0-1028.31.1 | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-nvidia-tegra | 6.8.0-1008.8 | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-oem-5.17 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-oem-6.0 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-oem-6.1 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-oem-6.11 | 6.11.0-1017.17 | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-oem-6.5 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-oem-6.8 | 6.8.0-1028.28 | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-oracle | 6.8.0-1026.27 | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-oracle-6.5 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-oracle-6.8 | 6.8.0-1026.27~22.04.1 | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-raspi | 6.8.0-1028.32 | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-raspi-realtime | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-realtime | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-realtime | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-riscv | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-riscv | 6.8.0-60.63.1 | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-riscv-5.19 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-riscv-6.5 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-riscv-6.8 | 6.8.0-62.65~22.04.1 | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-starfive-5.19 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-starfive-6.2 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:22.04:LTS | linux-starfive-6.5 | no fix listed | UBUNTU-CVE-2025-21655 |
| Ubuntu:24.04:LTS | linux-xilinx | 6.8.0-1017.18 | UBUNTU-CVE-2025-21655 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux | 21a091b970cdbcf3e8ff829234b51be6f9192766 – before 6b63308c28987c6010b1180c72a6db4df6c6803321a091b970cdbcf3e8ff829234b51be6f9192766 – before 8efff2aa2d95dc437ab67c5b4a9f1d3f367baa1021a091b970cdbcf3e8ff829234b51be6f9192766 – before a7085c3ae43b86d4b3d1b8275e6a67f14257e3b721a091b970cdbcf3e8ff829234b51be6f9192766 – before c9a40292a44e78f71258b8522655bffaf5753bdb |
| Linux | Linux | 6.1 |
References
- https://git.kernel.org/stable/c/6b63308c28987c6010b1180c72a6db4df6c68033
- https://git.kernel.org/stable/c/8efff2aa2d95dc437ab67c5b4a9f1d3f367baa10
- https://git.kernel.org/stable/c/a7085c3ae43b86d4b3d1b8275e6a67f14257e3b7
- https://git.kernel.org/stable/c/c9a40292a44e78f71258b8522655bffaf5753bdb
- https://project-zero.issues.chromium.org/issues/388499293
- https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html