UBUNTU-CVE-2026-80566: Medium severity ubuntu/linux-hwe-edge vulnerability
In the Linux kernel, the following vulnerability has been resolved: Input: hynitroncstxxx - validate touch count and finger IDs The driver allocates maxtouchnum input slots, which are indexed from zero through maxtouchnum - 1. The current check allows a finger ID equal to maxtouchnum to reach cst3xxreportcontact(). While the input core ignores out-of-range slot indices, reporting touch data without a valid slot change corrupts the touch state of the previously active slot. The touch count is read from the controller's report and is used to index the fixed-size report buffer without first checking its range. Reject counts larger than the supported number of touch slots before checking the trailing byte or parsing touch data. Reject finger IDs equal to or greater than maxtouchnum, and return immediately when an invalid finger ID is encountered so that corrupt touch frames are discarded instead of reporting partial contact state. The V821 Avaota F1 board configures the vendor driver with one touch slot, so finger ID 1 is already invalid on that device.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42~24.04.1 - Upgrade
Upgrade
ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1~24.04.1 - Upgrade
Upgrade
ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-42.42 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1016.17 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1016.18 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1015.16 - Upgrade
Upgrade
ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1 - Compensating control
In the hynitron_cstxxx driver, reject touch counts greater than max_touch_num before checking the trailing byte or parsing touch data; reject finger IDs greater than or equal to max_touch_num and return immediately on an invalid ID so corrupt touch frames are discarded.
Event History
Frequently Asked Questions
Which Ubuntu kernel packages are identified as affected?
The affected software list includes ubuntu/linux-riscv, ubuntu/linux-realtime, ubuntu/linux-azure, ubuntu/linux-gcp, ubuntu/linux-azure-fde, ubuntu/linux-gke, ubuntu/linux-hwe-edge, and ubuntu/linux-gkeop.
Which hardware configuration is specifically known to encounter an invalid finger ID?
The V821 Avaota F1 board is specifically called out. Its vendor driver is configured with one touch slot, making finger ID 1 invalid.
What malformed touch-controller values trigger the unsafe processing?
A reported touch count larger than the supported slot count can be used to index the fixed-size report buffer before validation. A finger ID equal to or greater than max_touch_num is also invalid and can corrupt the state of a previously active touch slot if processing continues.