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Linux KernelOperating system · Linux

CVE-2018-15471

HIGH · 7.8 CVSS v3.1 Published 2018-08-17
Fix available
A fix is available. Upgrade to 4.9.133 / 4.14.76 or later.
See remediation →
80/100
Remediation priority · High
Zero-click

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
An issue was discovered in xenvif_set_hash_mapping in drivers/net/xen-netback/hash.c in the Linux kernel through 4.18.1, as used in Xen through 4.11.x and other products. The Linux netback driver allows frontends to control mapping of requests to request queues. When processing a request to set or change this mapping, some input validation (e.g., for an integer overflow) was missing or flawed, leading to OOB access in hash handling. A malicious or buggy frontend may cause the (usually privileged) backend to make out of bounds memory accesses, potentially resulting in one or more of privilege escalation, Denial of Service (DoS), or information leaks.

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

A vulnerability exists in the Linux kernel's Xen netback driver (drivers/net/xen-netback/hash.c) in the xenvif_set_hash_mapping function. The function lacks proper input validation, specifically for integer overflow checks, when processing requests from frontends to set or change request queue mappings. A malicious or buggy frontend can trigger out-of-bounds memory accesses in the privileged backend, potentially leading to privilege escalation, DoS, or information leaks.

MitigationUpdate the Linux kernel to a version beyond 4.18.1 that contains the fix for this vulnerability. If immediate patching is not possible, consider restricting or validating frontend VMs and disabling the hash mapping feature if not required.

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:>= 4.7, < 4.9.133>= 4.10, < 4.14.76>= 4.15, < 4.18.14
Ubuntu LinuxOperating system
Affected:= 14.04= 16.04= 18.04= 18.10
XenOperating system
Affected:<= 4.11.0

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. Verify Xen virtualization environment
    Check if the system is running on Xen hypervisor or acting as Xen host: look for 'xen' in /proc/cpuinfo flags, check for /sys/hypervisor/ directory, or run 'xl list' (if xl toolstack is available) to list domains.
    Affected if System is NOT a Xen host (dom0 or driver domain); the vulnerability only affects the Xen netback driver in backend domains.
  2. Confirm kernel version is within affected range
    Run 'uname -r' to get the kernel version, then compare against: 4.7 to <4.9.133, OR 4.10 to <4.14.76, OR 4.15 to <4.18.14. For Ubuntu, check /boot/vmlinuz-* files or 'dpkg -l linux-image-*'.
    Affected if Kernel version does NOT fall within any of the listed version ranges; unpatched kernels in these ranges are vulnerable.
  3. Check if Xen netback driver is loaded
    Run 'lsmod | grep xenvif' to see if the xenvif (Xen virtual interface) module is loaded, or check 'modinfo xenvif' to verify driver presence. Also check 'ls -la /sys/module/xenvif' if the directory exists.
    Affected if The xenvif module is NOT loaded or present; the driver must be actively in use for the vulnerability to be exploitable.
  4. Identify if system acts as Xen backend
    Check if the system has active network backends: look for xen-netback in 'lsmod', check 'xl network-list <domid>' for domains with network vif interfaces, or inspect /var/log/xen/ for netback activity. A system with running guest VMs using paravirtual network interfaces is acting as a backend.
    Affected if System is NOT functioning as a Xen backend (no guest VMs with paravirtual network interfaces); the vulnerability requires a malicious or buggy frontend to communicate with this backend.

A system is affected only if it is a Xen host (dom0 or driver domain) running a vulnerable kernel version (4.7 to <4.9.133, 4.10 to <4.14.76, or 4.15 to <4.18.14) with the xenvif netback driver loaded and actively serving network requests to frontend VMs.

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.

From vendor data
Upgrade available Upgrade to 4.9.133 / 4.14.76 / 4.18.14 or later
Fixed in 4.9.1334.14.764.18.14
Interim mitigation

Update the Linux kernel to a version beyond 4.18.1 that contains the fix for this vulnerability. If immediate patching is not possible, consider restricting or validating frontend VMs and disabling the hash mapping feature if not required.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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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-2018-15471 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