CVE-2017-18509

CVE-2017-18509 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

Description

An issue was discovered in net/ipv6/ip6mr.c in the Linux kernel before 4.11. By setting a specific socket option, an attacker can control a pointer in kernel land and cause an inet_csk_listen_stop general protection fault, or potentially execute arbitrary code under certain circumstances. The issue can be triggered as root (e.g., inside a default LXC container or with the CAP_NET_ADMIN capability) or after namespace unsharing. This occurs because sk_type and protocol are not checked in the appropriate part of the ip6_mroute_* functions. NOTE: this affects Linux distributions that use 4.9.x longterm kernels before 4.9.187.

Frequently asked questions

What is CVE-2017-18509?
An issue was discovered in net/ipv6/ip6mr.c in the Linux kernel before 4.11. By setting a specific socket option, an attacker can control a pointer in kernel land and cause an inet_csk_listen_stop general protection fault, or potentially execute arbitrary code under certain circumstances. The issue can be triggered as root (e.g., inside a default LXC container or with the CAP_NET_ADMIN capability) or after namespace unsharing. This occurs because sk_type and protocol are not checked in the appropriate part of the ip6_mroute_* functions. NOTE: this affects Linux distributions that use 4.9.x longterm kernels before 4.9.187.
How severe is CVE-2017-18509?
CVE-2017-18509 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2017-18509 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (53rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-18509?
CVE-2017-18509 primarily affects Linux Linux Kernel. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2017-18509?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2017-18509 published?
CVE-2017-18509 was published on 2019-08-13 and last updated on 2026-06-17.

References

Affected products (5)

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