CVE-2025-21836
HIGH severity · CVSS 7.8
7.8CVSS HIGH
Summary
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.
Impact & exploitability
Attack vectorLocal
Attack complexityLow
Privileges requiredLow
User interactionNone
Confidentiality impactHigh
Integrity impactHigh
Availability impactHigh
Exploit probability (EPSS)0%
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Affected products we track (1)
Recommendation
Apply the vendor fix promptly. Open any affected product above for its exact safe version.
Official patch: https://git.kernel.org/stable/c/146a185f6c05ee263db715f860620606303c4633 ↗
Additional information
- NVD record
- https://git.kernel.org/stable/c/146a185f6c05ee263db715f860620606303c4633Patch
- https://git.kernel.org/stable/c/2a5febbef40ce968e295a7aeaa5d5cbd9e3e5ad4Patch
- https://git.kernel.org/stable/c/7d0dc28dae836caf7645fef62a10befc624dd17bPatch
- https://git.kernel.org/stable/c/8802766324e1f5d414a81ac43365c20142e85603Patch
- https://u1f383.github.io/slides/talks/2025_Hexacon-Deja_Vu_in_Linux_io_uring_Breaking_Memory_Sharing_Again_After_Generations_of_Fixes.pdf