What’s Vulnerable › Vulnerabilities

CVE-2019-18198

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2019-10-18 · updated 2026-06-17
• Weakness: CWE-772

Description

In the Linux kernel before 5.3.4, a reference count usage error in the fib6_rule_suppress() function in the fib6 suppression feature of net/ipv6/fib6_rules.c, when handling the FIB_LOOKUP_NOREF flag, can be exploited by a local attacker to corrupt memory, aka CID-ca7a03c41753.

Affected products

• Canonical Ubuntu Linux: 19.10
• Linux kernel: from 5.3 before 5.3.4 — fixed in 5.3.4

How to fix

Upgrade to a fixed version: Linux kernel 5.3.4. Check the vendor advisory for mitigations.

References

• https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.3.4
• https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=ca7a03c4175366a92cee0ccc4fec0038c3266e26
• https://github.com/torvalds/linux/commit/ca7a03c4175366a92cee0ccc4fec0038c3266e26
• https://launchpad.net/bugs/1847478
• https://security.netapp.com/advisory/ntap-20191031-0005/
• https://usn.ubuntu.com/4161-1/
• https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.3.4
• https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=ca7a03c4175366a92cee0ccc4fec0038c3266e26
• https://github.com/torvalds/linux/commit/ca7a03c4175366a92cee0ccc4fec0038c3266e26
• https://launchpad.net/bugs/1847478
• https://security.netapp.com/advisory/ntap-20191031-0005/
• https://usn.ubuntu.com/4161-1/

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