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Vulnerability · Published Mar 7, 2025 · Assigned by Linux

CVE-2025-21836io_uring/kbuf: reallocate buf lists on upgrade

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 83.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: io_uring/kbuf: reallocate buf lists on upgrade IORING_REGISTER_PBUF_RING can reuse an old struct io_buffer_list if it was created for legacy selected buffer and has been emptied. It violates the requirement that most of the field should stay stable after publish. Always reallocate it instead.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linuxno fix listedDEBIAN-CVE-2025-21836
Debian:13linux6.12.16-1DEBIAN-CVE-2025-21836
Debian:14linux6.12.16-1DEBIAN-CVE-2025-21836
Ubuntu:24.04:LTSlinux6.8.0-78.78UBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux6.8.0-78.78USN-7703-1
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-aws6.8.0-1035.37USN-7703-1
Ubuntu:24.04:LTSlinux-aws6.8.0-1035.37UBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1035.37~22.04.1UBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1035.37~22.04.1USN-7703-2
Ubuntu:24.04:LTSlinux-azure6.8.0-1034.39UBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-azure-6.116.11.0-1015.15~24.04.1UBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1034.39~22.04.1UBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-azure-nvidia6.8.0-1022.23UBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-gcp6.8.0-1036.38USN-7703-2
Ubuntu:24.04:LTSlinux-gcp6.8.0-1036.38UBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-gcp-6.116.11.0-1015.15~24.04.1UBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1036.38~22.04.1USN-7703-2
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1036.38~22.04.1UBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-gke6.8.0-1032.36UBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-gke6.8.0-1032.36USN-7703-4
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1019.21UBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1019.21USN-7703-2
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-hwe-6.116.11.0-26.26~24.04.1UBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-78.78~22.04.1USN-7703-4
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-78.78~22.04.1UBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-ibm6.8.0-1033.33UBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-ibm6.8.0-1033.33USN-7703-2
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1033.33~22.04.1UBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1033.33~22.04.1USN-7703-2
Ubuntu:24.04:LTSlinux-intelno fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-78.78.1USN-7703-1
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-78.78.1UBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.116.11.0-1014.15~24.04.1UBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-78.78.1~22.04.1USN-7703-1
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-78.78.1~22.04.1UBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1035.38UBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1035.38USN-7703-4
Ubuntu:24.04:LTSlinux-nvidia-6.116.11.0-1010.10UBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1035.38~22.04.1UBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1035.38~22.04.1USN-7703-4
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1035.38.1USN-7703-4
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1035.38.1UBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1009.9UBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-oem-6.116.11.0-1022.22UBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-oracle6.8.0-1032.33USN-7703-3
Ubuntu:24.04:LTSlinux-oracle6.8.0-1032.33UBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1032.33~22.04.1UBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1032.33~22.04.1USN-7703-3
Ubuntu:24.04:LTSlinux-raspi6.8.0-1035.39USN-7703-4
Ubuntu:24.04:LTSlinux-raspi6.8.0-1035.39UBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-78.78~22.04.1UBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2025-21836
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2025-21836
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1017.18UBUNTU-CVE-2025-21836

Affected products (as reported)

VendorProductVersions
Linux Linux 2fcabce2d7d34f69a888146dab15b36a917f09d4 – before 146a185f6c05ee263db715f860620606303c46332fcabce2d7d34f69a888146dab15b36a917f09d4 – before 7d0dc28dae836caf7645fef62a10befc624dd17b2fcabce2d7d34f69a888146dab15b36a917f09d4 – before 2a5febbef40ce968e295a7aeaa5d5cbd9e3e5ad42fcabce2d7d34f69a888146dab15b36a917f09d4 – before 8802766324e1f5d414a81ac43365c20142e85603
Linux Linux 5.19

References