UBUNTU-CVE-2026-68257: High severity ubuntu/linux vulnerability
In the Linux kernel, the following vulnerability has been resolved: drm/amdkfd: fix 32-bit overflow in CWSR total size calculation totalcwsrsize was computed in 32-bit before being used as a BO/SVM allocation size. With large ctxsaverestoreareasize and debugmemorysize multiplied by the XCC count, the product can wrap, yielding an undersized CWSR save area that firmware later overruns. Promote totalcwsrsize to u64 and use checkaddoverflow()/ checkmuloverflow() in both kfdqueueacquirebuffers() and kfdqueuereleasebuffers(). (cherry picked from commit 319f7e13423ae3f486b9aea82f9ad2d6af0ee608)
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
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ubuntu/linux-aws-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1014.14~24.04.1 - Upgrade
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ubuntu/linux-azure-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17~24.04.1 - Upgrade
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ubuntu/linux-azure-fde-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1016.16~24.04.1 - Upgrade
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ubuntu/linux-gcp-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1014.14~24.04.1 - Upgrade
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ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-38.38~24.04.4 - Upgrade
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ubuntu/linux-nvidia-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1024.25~24.04.1 - Upgrade
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ubuntu/linux-oracle-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1013.13~24.04.1 - Upgrade
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ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-38.38.1~24.04.1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-38.38 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1014.14 - Upgrade
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ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-azure-fdeto a version that resolves this vulnerability.Fixed in 7.0.0-1016.16 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1014.14 - Upgrade
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ubuntu/linux-gketo a version that resolves this vulnerability.Fixed in 7.0.0-1008.9 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1015.15 - Upgrade
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ubuntu/linux-nvidia-bosto a version that resolves this vulnerability.Fixed in 7.0.0-2022.23 - Upgrade
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ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1015.15 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1013.13 - Upgrade
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ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 7.0.0-38.38.1 - Upgrade
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ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-38.38.1 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Patch 319f7e13423ae3f486b9aea82f9ad2d6af0ee608
Event History
Frequently Asked Questions
What conditions are required to trigger this issue?
An attacker needs local access and low-level privileges. Exploitation also requires sufficiently large CWSR context save/restore and debug-memory sizes, multiplied by the XCC count, to cause the 32-bit total-size calculation to wrap.
Which Ubuntu kernel packages are listed as affected?
The advisory lists ubuntu/linux, ubuntu/linux-fips, ubuntu/linux-aws, ubuntu/linux-aws-fips, ubuntu/linux-azure, ubuntu/linux-azure-fips, ubuntu/linux-gcp, and ubuntu/linux-gcp-fips.
What is the consequence of a successful trigger?
The integer wrap can allocate an undersized CWSR save area. Firmware can then overrun that allocation, with high impacts to confidentiality, integrity, and availability.
What change addresses the vulnerability?
The fix promotes the total CWSR size calculation to u64 and adds checked addition and multiplication in kfd_queue_acquire_buffers() and kfd_queue_release_buffers().