CVE-2026-80836: crypto: virtio - bound the akcipher result length
In the Linux kernel, the following vulnerability has been resolved:
crypto: virtio - bound the akcipher result length
virtiocryptodataqakciphercallback() sets the result length from the device-reported response length without bounding it to the destination buffer, which was allocated for the original request length. sgcopyfrombuffer() then reads that many bytes from the destination buffer; a backend reporting a larger length over-reads adjacent kernel heap into the caller's scatterlist (an out-of-bounds read).
Clamp the reported length to the originally requested destination length. A conforming device reports no more than that, so valid results are unaffected.
Affected Software
Event History
Frequently Asked Questions
What must an attacker control to trigger the out-of-bounds read?
They would need a virtio crypto backend that reports an asymmetric-cipher result length larger than the destination buffer originally allocated for the request. A conforming device does not report a length larger than the requested destination length.
What is the impact of a malicious oversized response length?
The kernel can read adjacent heap memory beyond the destination buffer and copy it into the caller's scatterlist. This can expose unintended kernel heap data to the request recipient.
Is there a mitigation if the kernel cannot be updated immediately?
Use only trusted, conforming virtio crypto backends and prevent untrusted backends from servicing asymmetric-cipher requests. The vulnerable behavior depends on a backend supplying an oversized response length.