Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux Kernel | >= 5.19, < 6.6.79 |
References
- 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_Bre
FAQ
What is CVE-2025-21836?
CVE-2025-21836 is a vulnerability with a CVSS score of 5.5 (MEDIUM). 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 ...
How severe is CVE-2025-21836?
CVE-2025-21836 has been rated MEDIUM with a CVSS base score of 5.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2025-21836?
Check the references section above for vendor advisories and patch information. Affected products include: Linux Linux Kernel.