Linux: Out-of-bounds Read
CVE-2026-31484 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions ba21ab247a5be5382da7464b95afbe5f0e9aa503, 5170efd9c344c68a8075dcb8ed38d3f8a60e7ed4 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.12% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to ba21ab247a5be5382da7464b95afbe5f0e9aa503 or 5170efd9c344c68a8075dcb8ed38d3f8a60e7ed4, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.19.11 or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 1cba30bf9fdd6c982708f3587f609a30c370d889 up to, but not including, ba21ab247a5be5382da7464b95afbe5f0e9aa503; 1cba30bf9fdd6c982708f3587f609a30c370d889 up to, but not including, 5170efd9c344c68a8075dcb8ed38d3f8a60e7ed4; 6.19 | ba21ab247a5be5382da7464b95afbe5f0e9aa503, 5170efd9c344c68a8075dcb8ed38d3f8a60e7ed4 |
| Linux | Linux Kernel | 6.19.1 up to, but not including, 6.19.11; 6.19; 7.0 | 6.19.11 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H. Scored by CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: io_uring/fdinfo: fix OOB read in SQE_MIXED wrap check __io_uring_show_fdinfo() iterates over pending SQEs and, for 128-byte SQEs on an IORING_SETUP_SQE_MIXED ring, needs to detect when the second half of the SQE would be past the end of the sq_sqes array. The current check tests (++sq_head & sq_mask) == 0, but sq_head is only incremented when a 128-byte SQE is encountered, not on every iteration. The actual array index is sq_idx = (i + sq_head) & sq_mask, which can be sq_mask (the last slot) while the wrap check passes. Fix by checking sq_idx directly. Keep the sq_head increment so the loop still skips the second half of the 128-byte SQE on the next iteration.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Read
The product reads data past the end, or before the beginning, of the intended buffer.
How developers prevent this class of flaw
- Use a language that provides appropriate memory abstractions.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Out-of-bounds Read vulnerabilities
- 8.1 High severity
- 9.1 Critical severity
- 7.8 High severity
- 8.1 High severity
- 8.1 High severity
- 7.8 High severity
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