UBUNTU-CVE-2026-98157: Medium severity ubuntu/linux vulnerability
In the Linux kernel, the following vulnerability has been resolved: EDAC/devicesysfs: Use kstrtouint() for pollmsec to prevent truncation The pollmsec sysfs store file uses simplestrtoul() which accepts an unsigned long, but the target field (pollmsec) is unsigned int. On 64-bit systems, a value > UINTMAX is silently truncated when stored. Fix the mismatch by using kstrtouint() instead. This rejects values larger than UINTMAX at parse time, making truncation impossible. Also add a check for value < 1 to reject the 0-delay case, which would cause the poll work to spin without delay and consume 100% CPU.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
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ubuntu/linux-aws-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1119.126~20.04.1 - Upgrade
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ubuntu/linux-azure-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1125.134~20.04.1 - Upgrade
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ubuntu/linux-azure-fde-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1124.133~20.04.1 - Upgrade
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ubuntu/linux-gcp-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1120.130~20.04.1 - Upgrade
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ubuntu/linux-ibm-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1113.117~20.04.1 - Upgrade
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ubuntu/linux-intel-iotg-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1114.120~20.04.1 - Upgrade
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ubuntu/linux-lowlatency-hwe-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-197.207~20.04.1 - Upgrade
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ubuntu/linux-oracle-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1116.122~20.04.1 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 5.15.0-1120.130 - Upgrade
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ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42~24.04.1 - Upgrade
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ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1~24.04.1 - Upgrade
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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-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1015.16 - Upgrade
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ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1 - Configuration
Replace simple_strtoul() with kstrtouint() for the poll_msec sysfs store file, and reject values below 1 to prevent zero-delay polling and values above UINT_MAX from being silently truncated.
Linux kernel EDAC/device_sysfs poll_msec parsing and validation = Use kstrtouint() and reject values less than 1
Event History
Frequently Asked Questions
Who can trigger the excessive CPU consumption?
An attacker or local user needs low-privileged local access sufficient to write to the EDAC device poll_msec sysfs store file. The issue is local-only; the supplied vector does not indicate a network or user-interaction requirement.
What input causes the denial of service?
Writing 0 to poll_msec creates a zero-delay polling loop that can consume 100% CPU. On 64-bit systems, values greater than UINT_MAX can also be silently truncated before the fix.
How can I tell whether a system is exposed?
Exposure depends on whether the running Ubuntu kernel includes the EDAC device_sysfs change that parses poll_msec with kstrtouint() and rejects values below 1. A vulnerable implementation uses simple_strtoul() and stores the result in an unsigned int field.
What can be done before updating the kernel?
Restrict untrusted local users from writing to the affected EDAC poll_msec sysfs file. In particular, prevent writes of 0, which can make the polling work spin without delay and consume all CPU capacity.