What’s Vulnerable › Vulnerabilities

CVE-2019-20422

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-01-27 · updated 2026-06-17
• Weakness: CWE-755

Description

In the Linux kernel before 5.3.4, fib6_rule_lookup in net/ipv6/ip6_fib.c mishandles the RT6_LOOKUP_F_DST_NOREF flag in a reference-count decision, leading to (for example) a crash that was identified by syzkaller, aka CID-7b09c2d052db.

Affected products

• Linux kernel: 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://github.com/torvalds/linux/commit/7b09c2d052db4b4ad0b27b97918b46a7746966fa
• https://security.netapp.com/advisory/ntap-20200313-0003/
• https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.3.4
• https://github.com/torvalds/linux/commit/7b09c2d052db4b4ad0b27b97918b46a7746966fa
• https://security.netapp.com/advisory/ntap-20200313-0003/

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