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Linux KernelOperating system · Linux

CVE-2026-52959

HIGH · 7.8 CVSS v3.1 Published 2026-06-24
Fix available
A fix is available. Upgrade to 6.14 / 6.18.33 or later.
See remediation →
80/100
Remediation priority · High
Zero-click Patch available 8 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: virt: sev-guest: Do not use host-controlled page order in cleanup path When issuing an extended guest request (SVM_VMGEXIT_EXT_GUEST_REQUEST), get_ext_report() allocates a buffer to retrieve a certificate blob from the host, keeping track of its size in report_req->certs_len. However, the host may return SNP_GUEST_VMM_ERR_INVALID_LEN, indicating an invalid buffer size, as well as the expected length of such buffer. get_ext_report() subsequently updates report_req->certs_len with the host-controlled value, and cleans up the buffer by computing a page order from such value. This is incorrect, as the host-provided length may not match the page order of the original allocation, potentially resulting in corruption in the page allocator. Fix this by using alloc_pages_exact() instead, and reusing @npages to compute the size passed to free_pages_exact(). For consistency, also use @npages to compute the size when allocating the pages, even though this last change has no functional effect.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

In the Linux kernel's virt: sev-guest driver, the get_ext_report() function uses a host-controlled length value to compute page order during buffer cleanup. When the host returns SNP_GUEST_VMM_ERR_INVALID_LEN with an expected buffer size, the driver updates report_req->certs_len with this host-provided value and incorrectly computes page order from it, leading to page allocator corruption.

MitigationApply the kernel patch to use alloc_pages_exact() and free_pages_exact() with consistent npages tracking instead of recomputing page order from host-controlled values. This is a kernel source code fix requiring rebuild and deployment.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 6.13.8, < 6.14>= 6.14.1, < 6.18.33>= 6.19, < 7.0.10= 6.14= 7.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check kernel version
    Run 'uname -r' or check /proc/version to obtain the running kernel version
    Affected if Kernel version falls within affected ranges: >= 6.13.8 to < 6.14, >= 6.14.1 to < 6.18.33, >= 6.19 to < 7.0.10, or exactly 6.14 or 7.1
  2. Verify SEV-SNP is enabled
    Check for SNP support via 'cat /sys/kernel/security/sev_snp' or check dmesg for 'SEV-SNP' messages. Also check kernel cmdline for 'sev-snp' or 'amd-sev-snp' parameters.
    Affected if SEV-SNP is enabled or the kernel was built with CONFIG_AMD_SEV_SNP=y and the feature is active
  3. Check if sev-guest driver is loaded
    Run 'lsmod | grep sev_guest' or check /sys/module/sev_guest/version. Also verify /dev/sev-guest exists.
    Affected if The sev_guest module is loaded and the device interface is available

User is affected if running an affected kernel version AND SEV-SNP is enabled with the sev-guest driver active, allowing untrusted host control of buffer length to corrupt memory allocation.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 6.14 / 6.18.33 / 7.0.10 or later
Fixed in 6.146.18.337.0.10
Vendor patch git.kernel.org →
Interim mitigation

Apply the kernel patch to use alloc_pages_exact() and free_pages_exact() with consistent npages tracking instead of recomputing page order from host-controlled values. This is a kernel source code fix requiring rebuild and deployment.

Recommended fix High confidence

Linux Kernel 6.14.1, 6.18.33, 7.0.10 or later

  1. Identify the currently running Linux kernel version using `uname -r`
  2. Determine which kernel series your distribution uses (e.g., check /etc/os-release for Debian/Ubuntu, or `rpm -q kernel` for RHEL/CentOS)
  3. Upgrade the Linux kernel to version 6.14.1 or later for the 6.14.x stable branch
  4. Alternatively, upgrade to version 6.18.33 or later for the 6.18.x stable branch
  5. Alternatively, upgrade to version 7.0.10 or later for the 7.0.x stable branch
  6. After kernel upgrade, reboot the system to load the patched kernel
  7. Verify the fix is applied by checking the kernel version matches one of the fixed releases
Caveat Kernel upgrades may require reboot and could introduce regressions in drivers or features; ensure compatibility with local workloads before production deployment

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing8.0 h
  • Review / QA3.0 h
17.0 hours of engineering $2,860
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-52959 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data