Skip to main content
Meet us at Black Hat USA 2026— Las Vegas, August 1–6Book a Meeting
Mallory
High

Linux kernel crypto: ccp out-of-bounds read and kernel memory leak in SEV CPU ID retrieval

IdentifiersCVE-2026-31697CWE-125

CVE-2026-31697 is a Linux kernel vulnerability in the crypto: ccp subsystem, specifically in the SEV/PSP CPU ID retrieval ioctl path. When retrieving the CPU ID blob, the kernel could attempt to copy data to userspace even if the underlying PSP firmware command failed. If the failure was caused by an invalid length condition, such as a userspace buffer that was too small, the code could use the firmware-reported required size when calling copy_to_user(), even though the kernel-allocated buffer was smaller. This results in a slab out-of-bounds read from kernel memory during the copy operation and can leak adjacent kernel memory to userspace. The reported fault path includes sev_ioctl_do_get_id2() in drivers/crypto/ccp/sev-dev.c, with KASAN detecting the issue as a slab-out-of-bounds read in _copy_to_user(). The fix prevents copying the ID blob to userspace when the PSP command fails and adds a WARN for inconsistent driver-success versus firmware-error states.

Share:
For your environment

Are you exposed to this one?

Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.

ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can trigger an out-of-bounds read of kernel heap memory and copy unintended kernel data to userspace, resulting in an information disclosure. Depending on the surrounding heap state, this may expose sensitive kernel memory contents and may also cause kernel instability or faulting during the copy path. Available scoring in the provided content also indicates potential availability impact in addition to confidentiality impact.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce exposure by restricting local access to the vulnerable ioctl interface and limiting use of AMD SEV/PSP management functionality to trusted privileged users only. Systems that do not expose or use the affected SEV CPU ID retrieval path are less likely to be practically reachable. Standard hardening measures such as minimizing local shell access and restricting access to /dev/sev or equivalent device interfaces may reduce exploitability, but the definitive mitigation is to apply the kernel fix.

Remediation

Patch, then assume compromise.

Upgrade to a Linux kernel release containing the upstream fix for CVE-2026-31697 in crypto: ccp. The fix changes the SEV CPU ID retrieval logic so that the kernel does not copy the ID blob to userspace if the PSP firmware command failed, and it warns on inconsistent success/error reporting from the firmware command path. Vendor backports are available in multiple SUSE kernel updates referenced in the provided content; deploy the relevant patched kernel package for the affected distribution and reboot into the updated kernel.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
LinuxLinux Kerneloperating_system

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity

Community discussion across Reddit, Mastodon, and other social sources.