Vulnerability Snapshot
CVE-2017-18017 is rated CRITICAL — exploitation is trivial or already observed in the wild and impact is severe. Patch immediately, not on the next maintenance window.
Affected technology: linux_kernel, debian_linux, eos, arx, caas_platform, plus 5 other product variants.
Executive Summary
The tcpmss_mangle_packet function in net/netfilter/xt_TCPMSS.c in the Linux kernel before 4.11, and 4.9.x before 4.9.36, allows remote attackers to cause a denial of service (use-after-free and memory corruption) or possibly have unspecified other impact by leveraging the presence of xt_TCPMSS in an iptables action.
Why It Matters
CVE-2017-18017 is rated CRITICAL severity, requiring immediate attention from security teams.
CVSS Base Score: 9.8/10
Affected Technologies
Vendors: linux, debian, arista, f5, suse, opensuse, openstack, canonical, redhat
Products: linux_kernel, debian_linux, eos, arx, caas_platform, linux_enterprise_debuginfo, linux_enterprise_module_for_public_cloud, linux_enterprise_point_of_sale, openstack_cloud, leap, linux_enterprise_desktop, linux_enterprise_high_availability, linux_enterprise_high_availability_extension, linux_enterprise_live_patching, linux_enterprise_real_time_extension, linux_enterprise_server, linux_enterprise_software_development_kit, linux_enterprise_workstation_extension, cloud_magnum_orchestration, ubuntu_linux, mrg_realtime, enterprise_linux_desktop, enterprise_linux_eus, enterprise_linux_for_real_time, enterprise_linux_for_real_time_for_nfv, enterprise_linux_server, enterprise_linux_server_aus, enterprise_linux_server_tus, enterprise_linux_workstation
🛡️What Defenders Should Check
Use Vulnios to continuously monitor your exposure to CVE-2017-18017 and similar vulnerabilities.
References & Sources
How Vulnios Detects This
Vulnios scans for this vulnerability using Trivy and Grype for CVE matching against your container images and OS package manifests. Run a scan against your environment to see whether you are exposed; findings are linked back to the original CVE record so triage starts with the patch path already known.
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Affected Products
Sources
Related Threat Alerts
- Critical Vulnerability: CVE-2019-14897 — linux, debian — linux_kernel, debian_linux
- Critical Vulnerability: CVE-2019-14901 — linux, fedoraproject — linux_kernel, fedora
- Critical Vulnerability: CVE-2019-14896 — linux, fedoraproject — linux_kernel, fedora
- Critical Vulnerability: CVE-2019-14895 — linux, debian — linux_kernel, debian_linux
- Critical Vulnerability: CVE-2019-18805 — linux, opensuse — linux_kernel, leap
- Critical Vulnerability: CVE-2019-18814 — linux — linux_kernel
Frequently Asked Questions
What is CVE-2017-18017?
CVE-2017-18017 is a critical-severity vulnerability tracked under the Common Vulnerabilities and Exposures program. The tcpmss_mangle_packet function in net/netfilter/xt_TCPMSS.c in the Linux kernel before 4.11, and 4.9.x before 4.9.36, allows remote attackers to cause a denial of service (use-after-free and memory
Am I affected?
Check whether your environment runs linux_kernel, debian_linux, eos, arx, caas_platform. If you operate any of those, treat yourself as in scope until you have evidence otherwise. A Vulnios scan will identify the exact assets carrying the affected version.
How urgent is the response?
Critical: do not wait for your normal patch cycle. Verify exposure today, apply the vendor patch immediately, and add detection rules for any post-exploit indicators.
How do I remediate?
Apply the vendor patch listed in the upstream advisory linked under Sources. If the patch is not yet available, follow the vendor-supplied workaround (often a config flag or feature disable) and add detections for the published exploit pattern in your SIEM. Re-scan after the patch lands to confirm the finding clears.
Where can I track exploitation activity?
Watch CISA's Known Exploited Vulnerabilities catalog for CVE-2017-18017. Cross-reference with public exploit databases and your own SIEM/IDS for indicator-of-compromise patterns. Vulnios tracks KEV status automatically and surfaces it on the asset findings view.
How does Vulnios help with this?
Vulnios continuously cross-references your asset inventory against the live CVE feed (NVD, vendor advisories, CISA KEV, and curated OSINT). When a new CVE matches your environment, you get a prioritized finding with the severity, KEV status, exploit-prediction (EPSS), and a direct path to the vendor patch. You can start a free scan from the homepage.
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