Linux: Out-of-bounds Read
CVE-2026-63943 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 bcfb4833cd4078a1a356ef451838b75cd233099e, 37ec54abfdd63a63fd50734a9c4e4cbc1e5795af, 9749db57233b396353ad5dee81eec9d9880c9246 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 0.16% 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 bcfb4833cd4078a1a356ef451838b75cd233099e or 37ec54abfdd63a63fd50734a9c4e4cbc1e5795af or 9749db57233b396353ad5dee81eec9d9880c9246 or 6346b0895b574ce45f3747b9c508c72f70e6abef, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.6.143 or 6.12.93 or 6.15 or 6.18.35, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | cbc82e7db16d59c301457312a624a7de2c03cd4a up to, but not including, bcfb4833cd4078a1a356ef451838b75cd233099e; 302a0cd0bbc450998429a3f4267970a4b93251a8 up to, but not including, 37ec54abfdd63a63fd50734a9c4e4cbc1e5795af; 4ef46367073b107ec22f46fe5f12176e87c238e8 up to, but not including, 9749db57233b396353ad5dee81eec9d9880c9246; 4ef46367073b107ec22f46fe5f12176e87c238e8 up to, but not including, 6346b0895b574ce45f3747b9c508c72f70e6abef; 4ef46367073b107ec22f46fe5f12176e87c238e8 up to, but not including, 6cdc46b38cf146ce81d4831b6472dbf7731849a2; a7e3ddd1d9a3d0b26465ed01d464e3c05479ebc8; 6.6.91 up to, but not including, 6.6.143; 6.12.29 up to, but not including, 6.12.93; and 2 more ranges | bcfb4833cd4078a1a356ef451838b75cd233099e, 37ec54abfdd63a63fd50734a9c4e4cbc1e5795af, 9749db57233b396353ad5dee81eec9d9880c9246, 6346b0895b574ce45f3747b9c508c72f70e6abef, 6cdc46b38cf146ce81d4831b6472dbf7731849a2, 6.6.143 |
| Linux | Linux Kernel | 6.6.91 up to, but not including, 6.6.143; 6.12.29 up to, but not including, 6.12.93; 6.14.7 up to, but not including, 6.15; 6.15.1 up to, but not including, 6.18.35; 6.19 up to, but not including, 7.0.12; 6.15; 7.1 | 6.6.143, 6.12.93, 6.15, 6.18.35, 7.0.12 |
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 NVD.
Official description
In the Linux kernel, the following vulnerability has been resolved: Input: xpad - fix out-of-bounds access for Share button xpadone_process_packet() receives len directly from urb->actual_length and uses it to index the share-button byte at data[len - 18] or data[len - 26]. Since both len and data[0] are under the device's control, a broken controller can send a GIP_CMD_INPUT packet with actual_length < 18 (e.g. 5 bytes) and reach this code path, causing accesses beyond the actual array. Fix this by calculating the offset and checking bounds against the packet length.
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
- git.kernel.org/stable/c/37ec54abfdd63a63fd50734a9c4e4cbc1e5795af
- git.kernel.org/stable/c/6346b0895b574ce45f3747b9c508c72f70e6abef
- git.kernel.org/stable/c/6cdc46b38cf146ce81d4831b6472dbf7731849a2
- git.kernel.org/stable/c/9749db57233b396353ad5dee81eec9d9880c9246
- git.kernel.org/stable/c/bcfb4833cd4078a1a356ef451838b75cd233099e
Recent Out-of-bounds Read vulnerabilities
- 7.1 High severity
- 7.8 High severity
- 7.3 High severity
- 7.1 High severity
- 7.8 High severity
- 9.8 Critical severity
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