Division by zero in Linux kernel - CVE-2026-89790
Published: September 17, 2026
Vulnerability identifier: #VU150501
CSH Severity: Low
CVSS v4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-89790
CWE-ID: CWE-369
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to a divide-by-zero error in rt6_multipath_rebalance() when a concurrent ignore_routes_with_linkdown update causes the total eligible nexthop weight to be zero. A local user can concurrently update ignore_routes_with_linkdown while adding an IPv6 multipath route to cause a denial of service.
Affected software
Linux kernel
How to mitigate CVE-2026-89790
Install security update from vendor's repository.