Linux: Out-of-bounds Read
CVE-2026-43427 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 638328ca9c17ae6511ad62198c57bae32ffa3c91, 170e8daca24da6edb4be82ab01abf44e87af387b, c8fa96ed021923dae147bcd9f9205b8df7b82360 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 0.13% 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 638328ca9c17ae6511ad62198c57bae32ffa3c91 or 170e8daca24da6edb4be82ab01abf44e87af387b or c8fa96ed021923dae147bcd9f9205b8df7b82360 or 4ee3062bf2c9a722afef429826e8607eaf3fc6a0, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.253 or 5.15.203 or 6.1.167 or 6.6.130, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | afba937e540c902c989cd516fd97ea0c8499bb27 up to, but not including, 638328ca9c17ae6511ad62198c57bae32ffa3c91; afba937e540c902c989cd516fd97ea0c8499bb27 up to, but not including, 170e8daca24da6edb4be82ab01abf44e87af387b; afba937e540c902c989cd516fd97ea0c8499bb27 up to, but not including, c8fa96ed021923dae147bcd9f9205b8df7b82360; afba937e540c902c989cd516fd97ea0c8499bb27 up to, but not including, 4ee3062bf2c9a722afef429826e8607eaf3fc6a0; afba937e540c902c989cd516fd97ea0c8499bb27 up to, but not including, 276aef0fd2b92f41b920ac891c72cadeee957934; afba937e540c902c989cd516fd97ea0c8499bb27 up to, but not including, 67ed312124bb1b61858778ac0b985b48961c862a; afba937e540c902c989cd516fd97ea0c8499bb27 up to, but not including, e3c874b05901dc519054b5107d16620e6d2b5fea; afba937e540c902c989cd516fd97ea0c8499bb27 up to, but not including, 8df672bfe3ec2268c2636584202755898e547173; and 1 more ranges | 638328ca9c17ae6511ad62198c57bae32ffa3c91, 170e8daca24da6edb4be82ab01abf44e87af387b, c8fa96ed021923dae147bcd9f9205b8df7b82360, 4ee3062bf2c9a722afef429826e8607eaf3fc6a0, 276aef0fd2b92f41b920ac891c72cadeee957934, 67ed312124bb1b61858778ac0b985b48961c862a |
| Linux | Linux Kernel | 2.6.26.1 up to, but not including, 5.10.253; 5.11 up to, but not including, 5.15.203; 5.16 up to, but not including, 6.1.167; 6.2 up to, but not including, 6.6.130; 6.7 up to, but not including, 6.12.78; 6.13 up to, but not including, 6.18.19; 6.19 up to, but not including, 6.19.9; 2.6.26; and 1 more ranges | 5.10.253, 5.15.203, 6.1.167, 6.6.130, 6.12.78, 6.18.19 |
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: usb: class: cdc-wdm: fix reordering issue in read code path Quoting the bug report: Due to compiler optimization or CPU out-of-order execution, the desc->length update can be reordered before the memmove. If this happens, wdm_read() can see the new length and call copy_to_user() on uninitialized memory. This also violates LKMM data race rules [1]. Fix it by using WRITE_ONCE and memory barriers.
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.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/170e8daca24da6edb4be82ab01abf44e87af387b
- git.kernel.org/stable/c/276aef0fd2b92f41b920ac891c72cadeee957934
- git.kernel.org/stable/c/4ee3062bf2c9a722afef429826e8607eaf3fc6a0
- git.kernel.org/stable/c/638328ca9c17ae6511ad62198c57bae32ffa3c91
- git.kernel.org/stable/c/67ed312124bb1b61858778ac0b985b48961c862a
- git.kernel.org/stable/c/8df672bfe3ec2268c2636584202755898e547173
- git.kernel.org/stable/c/c8fa96ed021923dae147bcd9f9205b8df7b82360
- git.kernel.org/stable/c/e3c874b05901dc519054b5107d16620e6d2b5fea
Recent Out-of-bounds Read vulnerabilities
- 7.1 High severity
- 8.2 High severity
- 7.1 High severity
- 7.1 High severity
- 9.1 Critical severity
- 9.1 Critical severity
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