Medium [CVE-2026-68271] fix reversed error cleanup order in ucopy functions
This medium-severity Red Hat Linux advisory covers CVE-2026-68271 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat package: kernel.
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Summary
In the Linux kernel, the following vulnerability has been resolved: drm/nouveau: fix reversed error cleanup order in ucopy functions nouveau_uvmm_vm_bind_ucopy() and nouveau_exec_ucopy() place their error cleanup labels in allocation order rather than reverse allocation order.
On a u_memcpya() failure for in_sync.s, the goto to err_free_ops (or err_free_pushs) frees the first allocation and then falls through to err_free_ins, which calls u_free() on args->in_sync.s.
Since args->in_sync.s still holds the ERR_PTR returned by the failed u_memcpya(), and ERR_PTR values are not caught by ZERO_OR_NULL_PTR(), kvfree() proceeds to dereference it, which can result in a kernel oops. A failure for out_sync.s instead jumps to err_free_ins and skips freeing the first allocation, leading to a memory leak.
Fix by swapping the cleanup label order so resources are freed in the correct reverse allocation sequence. An issue with the error cleanup order in `ucopy` functions can lead to incorrect memory deallocation.
This can result in a system crash, also known as a kernel oops, or a memory leak, potentially causing a denial of service. This issue affects NVIDIA nouveau GPUs. ucopy error paths free resources in allocation order instead of reverse order, causing double-free.
Systems without nouveau are not affected.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 2 days ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 2 days ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 2 days ago·verify at source
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