High 7.8Published Mar 7, 2025

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

Updated under an hour ago (Oct 28, 2026, 6:10 AM ET)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

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: 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 15, 2026
First seen by InfoSec Signals: Oct 15, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 2fcabce2d7d34f69a888146dab15b36a917f09d4 before 146a185f6c05ee263db715f860620606303c4633; from 2fcabce2d7d34f69a888146dab15b36a917f09d4 before 7d0dc28dae836caf7645fef62a10befc624dd17b; 2fcabce2d7d34f69a888146dab15b36a917f09d4 builds before 2a5febbef40ce968e295a7aeaa5d5cbd9e3e5ad4; from 2fcabce2d7d34f69a888146dab15b36a917f09d4 before 8802766324e1f5d414a81ac43365c20142e85603	CNA record
linux linux_kernel linux:linux_kernel	from 5.19 before 6.6.79; from 6.7 before 6.12.16; from 6.13 before 6.13.4; 6.14; 6.14	NVD

References

References

https://git.kernel.org/stable/c/146a185f6c05ee263db715f860620606303c4633	patch
https://git.kernel.org/stable/c/7d0dc28dae836caf7645fef62a10befc624dd17b	patch
https://git.kernel.org/stable/c/2a5febbef40ce968e295a7aeaa5d5cbd9e3e5ad4	patch
https://git.kernel.org/stable/c/8802766324e1f5d414a81ac43365c20142e85603	patch
https://u1f383.github.io/slides/talks/2025_Hexacon-Deja_Vu_in_Linux_io_uring_Breaking_Memory_Sharing_Again_After_Generations_of_Fixes.pdf

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.