CVE-2026-80836
NoneCVSS
—
EPSS
0.2%
Published
Sep 4, 2026
CISA due date
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Cloudanix analysis
A bug in the Linux kernel's handling of encrypted operations for virtual machines could let a malicious virtual device read nearby memory contents and expose private information.
- Exploitation
- Local Privilege
- Attacker needs
- Local User
- Complexity
- Moderate
- Impact
- Data Exposure
- Component
- OS kernel
- Class
- Information Disclosure
- Remediation
- Upgrade
- Effort
- Medium
- Patch risk
- Low
What it actually does
Out-of-bounds read in virtio_crypto_dataq_akcipher_callback allowing device-reported result length to exceed the allocated destination buffer, so sg_copy_from_buffer copies adjacent kernel heap into the caller's scatterlist.
Why it matters to the business
Kernel memory disclosure in virtualized environments may leak sensitive data such as cryptographic keys or other internal structures to untrusted backends, increasing risk of data exposure on systems using virtio crypto acceleration.
How an attack unfolds
An attacker who controls or emulates a virtio crypto backend sends an akcipher response with an inflated result length; the kernel callback uses this length without clamping, causing an over-read of adjacent heap memory into the destination scatterlist.
How to fix it
Apply the upstream fix that clamps the reported length to the originally requested destination length before calling sg_copy_from_buffer; rebuild and deploy the patched kernel on all affected systems.
How to confirm the fix worked
Confirm the clamping statement exists in virtio_crypto_dataq_akcipher_callback and that the function no longer trusts the device-reported length beyond the request size; test with a conforming device that returns exactly the requested length.
Typical attack path
- Gain control of the virtio crypto backend or hypervisor device emulation
- Initiate an akcipher request from the guest
- Return a response reporting a result length larger than the original destination buffer
- Observe or exfiltrate the over-read kernel heap contents delivered via sg_copy_from_buffer
How to detect it
Review kernel logs for virtio_crypto akcipher callback entries, inspect scatterlist handling around crypto requests, and correlate with backend-reported lengths if device emulation logs are available.
What your security team should do
- Apply kernel updates containing the length clamp as soon as available
- Limit use of virtio crypto devices to trusted backends only
- Monitor kernel logs for virtio crypto anomalies or unexpected scatterlist behavior
The record
In the Linux kernel, the following vulnerability has been resolved: crypto: virtio - bound the akcipher result length virtio_crypto_dataq_akcipher_callback() 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. sg_copy_from_buffer() 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 packages
| Ecosystem | Package | Introduced | Fixed |
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