Missing Release of Resource after Effective Lifetime Affecting perf6.18-debuginfo package, versions <1:6.18.36-69.134.amzn2023
Threat Intelligence
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Test your applications- Snyk IDSNYK-AMZN2023-PERF618DEBUGINFO-18062234
- published21 Jul 2026
- disclosed1 Jul 2026
Introduced: 1 Jul 2026
NewCVE-2026-53345 (opens in a new tab)How to fix?
Upgrade Amazon-Linux:2023 perf6.18-debuginfo to version 1:6.18.36-69.134.amzn2023 or higher.
This issue was patched in ALAS2023-2026-1925.
NVD Description
Note: Versions mentioned in the description apply only to the upstream perf6.18-debuginfo package and not the perf6.18-debuginfo package as distributed by Amazon-Linux.
See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
KVM: Don't WARN if memory is dirtied without a vCPU when the VM is dying
When marking a page dirty, complain about not having a running/loaded vCPU if and only if the VM is still alive, i.e. its refcount is non-zero. This will allow fixing a memory leak for x86 SEV-ES guests without hitting what is effectively a false positive on the WARN.
For some SEV-ES VM-Exits, KVM keeps a writable mapping of a guest page across an exit to userspace, and typically unmaps the page on the next KVM_RUN. But if userspace never calls KVM_RUN after such an exit, then KVM needs to unmap the page when the vCPU is destroyed, which in turn triggers the WARN about not having a running vCPU.
Alternatively, SEV-ES could temporarily load the vCPU to suppress the WARN, as is done in nested_vmx_free_vcpu() (but for completely unrelated reasons; suppressing WARN from nested_put_vmcs12_pages() is pure happenstance). But loading a vCPU during destruction is gross (ideally nVMX code would be cleaned up), risks complicating the SEV-ES code (KVM would need to ensure the temporarily load()+put() only runs when the vCPU isn't already loaded), and is ultimately pointless.
The motivation for the WARN is to guard against KVM dirtying guest memory without pushing the corresponding GFN to the active vCPU's dirty ring, e.g. to ensure userspace doesn't miss a dirty page. But for the VM's refcount to reach zero, there can't be any userspace mappings to the dirty ring, as mapping the dirty ring requires doing mmap() on the vCPU FD. I.e. if userspace had a valid mapping for the dirty ring, then the vCPU file and thus the owning VM would still be alive. And so since userspace can't possibly reach the dirty ring, whether or not KVM technically "misses" a push to the dirty ring is irrelevant.
References
- http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-53345
- https://git.kernel.org/stable/c/033d39e41fc30f484f4e4f37fb4cd76b12cbb18e
- https://git.kernel.org/stable/c/343e95c8ecc40e0738975ef4ee24c0c35e800e6b
- https://git.kernel.org/stable/c/66a8e7ddd901023c89a2733494d827eca3f9c1b0
- https://git.kernel.org/stable/c/8618004d3e897c0f1b71d9a9ab860461289bb89a
- https://git.kernel.org/stable/c/99d7d43784ae3235026581e9bf892c036e04c8e6