CVE-2018-15471
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.
| Software | From | Fixed in |
|---|---|---|
| xen / xen | - | 4.11.0.x |
| canonical / ubuntu_linux | 16.04 | 16.04.x |
| canonical / ubuntu_linux | 14.04 | 14.04.x |
| canonical / ubuntu_linux | 18.04 | 18.04.x |
| canonical / ubuntu_linux | 18.10 | 18.10.x |
| linux / linux_kernel | 4.10 | 4.14.76 |
| linux / linux_kernel | 4.7 | 4.9.133 |
| linux / linux_kernel | 4.15 | 4.18.14 |
- http://xenbits.xen.org/xsa/advisory-270.html
- https://bugs.chromium.org/p/project-zero/issues/detail?id=1607
- https://lists.debian.org/debian-lts-announce/2019/03/msg00017.html
- https://usn.ubuntu.com/3819-1/
- https://usn.ubuntu.com/3820-1/
- https://usn.ubuntu.com/3820-2/
- https://usn.ubuntu.com/3820-3/
- https://www.debian.org/security/2018/dsa-4313
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Frequently Asked Questions
A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.
CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.
A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.
Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.
Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.
SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.