Linux: Out-of-bounds Read
CVE-2026-63904 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 e794bd67b3faf98af46f958897f6b91412c7d2a9, e3eec3005de44e7f37d8d7724be636446516ab42, ae87f505917e703ae3b487d9663d78826ff43608 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 0.17% 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 e794bd67b3faf98af46f958897f6b91412c7d2a9 or e3eec3005de44e7f37d8d7724be636446516ab42 or ae87f505917e703ae3b487d9663d78826ff43608 or 5de7df75ef3a2756b25fe3d582a4a2970444fe5a, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.259 or 5.15.210 or 6.1.176 or 6.6.143, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | dbf3e7f654c0f06a932b8fcafac78de9d0b81d68 up to, but not including, e794bd67b3faf98af46f958897f6b91412c7d2a9; dbf3e7f654c0f06a932b8fcafac78de9d0b81d68 up to, but not including, e3eec3005de44e7f37d8d7724be636446516ab42; dbf3e7f654c0f06a932b8fcafac78de9d0b81d68 up to, but not including, ae87f505917e703ae3b487d9663d78826ff43608; dbf3e7f654c0f06a932b8fcafac78de9d0b81d68 up to, but not including, 5de7df75ef3a2756b25fe3d582a4a2970444fe5a; dbf3e7f654c0f06a932b8fcafac78de9d0b81d68 up to, but not including, 69020fa089f1bf0e1a10a15265f31b143a846409; dbf3e7f654c0f06a932b8fcafac78de9d0b81d68 up to, but not including, 75f6d3da2cc646983f41807ef98851569c12bca9; dbf3e7f654c0f06a932b8fcafac78de9d0b81d68 up to, but not including, f141b01eaa58ac7e323931d670318aa247bff087; dbf3e7f654c0f06a932b8fcafac78de9d0b81d68 up to, but not including, 52f2ad3f7e5eb3b5908e1d685d4342519dc9cfcd; and 1 more ranges | e794bd67b3faf98af46f958897f6b91412c7d2a9, e3eec3005de44e7f37d8d7724be636446516ab42, ae87f505917e703ae3b487d9663d78826ff43608, 5de7df75ef3a2756b25fe3d582a4a2970444fe5a, 69020fa089f1bf0e1a10a15265f31b143a846409, 75f6d3da2cc646983f41807ef98851569c12bca9 |
| Linux | Linux Kernel | 4.6 up to, but not including, 5.10.259; 5.11 up to, but not including, 5.15.210; 5.16 up to, but not including, 6.1.176; 6.2 up to, but not including, 6.6.143; 6.7 up to, but not including, 6.12.93; 6.13 up to, but not including, 6.18.35; 6.19 up to, but not including, 7.0.12; 7.1 | 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35 |
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: usbtmc: check URB actual_length for interrupt-IN notifications USBTMC devices can use an optional interrupt endpoint for notification messages. These typically contain two-byte headers indicating the payload format, but the driver does not check if these headers are present before accessing the data buffers. In cases where the URB actual_length is not enough to fit these headers, the driver will either cause an out-of-bounds read, or consume stale leftover data from a previous notification. Fix by checking if actual_data contains enough bytes for the headers, otherwise resubmit URB to the interrupt endpoint.
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/52f2ad3f7e5eb3b5908e1d685d4342519dc9cfcd
- git.kernel.org/stable/c/5de7df75ef3a2756b25fe3d582a4a2970444fe5a
- git.kernel.org/stable/c/69020fa089f1bf0e1a10a15265f31b143a846409
- git.kernel.org/stable/c/75f6d3da2cc646983f41807ef98851569c12bca9
- git.kernel.org/stable/c/ae87f505917e703ae3b487d9663d78826ff43608
- git.kernel.org/stable/c/e3eec3005de44e7f37d8d7724be636446516ab42
- git.kernel.org/stable/c/e794bd67b3faf98af46f958897f6b91412c7d2a9
- git.kernel.org/stable/c/f141b01eaa58ac7e323931d670318aa247bff087
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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