CVE-2025-21836

io_uring/kbuf: reallocate buf lists on upgrade

MEDIUM
5.5
CVSS Score
Published: March 7, 2025 at 09:09 AM UTC
Updated: October 15, 2026 at 10:18 PM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

5.19 ≤ v < 6.6.796.13 ≤ v < 6.13.46.7 ≤ v < 6.12.162fcabce2d7d34f69a888146dab15b36a917f09d46.146.14 rc16.14 rc2
Vendor states this is fixed in 146a185f6c05ee263db715f860620606303c4633 (fixed)
Vendor states this is fixed in 2a5febbef40ce968e295a7aeaa5d5cbd9e3e5ad4 (fixed)
Vendor states this is fixed in 7d0dc28dae836caf7645fef62a10befc624dd17b (fixed)
Vendor states this is fixed in 8802766324e1f5d414a81ac43365c20142e85603 (fixed)
Vendor states this is fixed in 5.19 (unaffected)
Vendor states this is fixed in 6.12.16 (unaffected)
Vendor states this is fixed in 6.13.4 (unaffected)
Vendor states this is fixed in 6.14 (unaffected)
Vendor states this is fixed in 6.6.79 (unaffected)

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
NVD-CWE-noinfo

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