ipv6: avoid divide by zero in rt6_multipath_rebalance
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 6.18.52, 7.2.6
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
In the Linux kernel, the following vulnerability has been resolved: ipv6: avoid divide by zero in rt6_multipath_rebalance rt6_multipath_rebalance() calculates the total eligible nexthop weight in one pass and programs upper bounds in a second pass. Since RTM_NEWROUTE is RTNL-free, a concurrent ignore_routes_with_linkdown update can make the first pass return zero while the second sees an eligible nexthop, causing rt6_upper_bound_set() to divide by zero. UBSAN: division-overflow in net/ipv6/route.c:4845:17 Oops: divide error: 0000 [#1] SMP KASAN NOPTI rt6_upper_bound_set() net/ipv6/route.c:4845 rt6_multipath_rebalance() fib6_add_rt2node() ip6_route_multipath_add() inet6_rtm_newroute() Skip upper-bound calculation when the first pass reports a zero total. This respects the lock-free performance considerations here and solves insecure scenarios.
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
From bd11ff421d36abdb585b9104fa70057bf01b3110 · fixed in f30cf8fd9872299c0c27f9916252ba2b9f422dce; From bd11ff421d36abdb585b9104fa70057bf01b3110 · fixed in f82b5dbb2fef65b52a62d5ffe05e0483c4385a83; From bd11ff421d36abdb585b9104fa70057bf01b3110 · fixed in d2c26c2911dd1a363c488add4fb63eb5f0f28f87
- Linux Linux
6.16
- KernelLinux
From 6.16.0 · fixed in 6.18.52; From 6.19.0 · fixed in 7.2.6