Linux Kernel: Stale IPv6 Route Leak Due to fib6 Rule Suppression
CVE-2026-74581 Published on August 21, 2026
net: ipv6: clear suppressed fib6 rule result
In the Linux kernel, the following vulnerability has been resolved:
net: ipv6: clear suppressed fib6 rule result
fib6_rule_suppress() drops a suppressed route with ip6_rt_put_flags(),
but leaves res->rt6 pointing at the released rt6_info.
If no later rule supplies a replacement, fib6_rule_lookup() still sees
res.rt6 and returns that stale dst to its caller. A suppressing rule can
therefore leak a released route back to rt6_lookup(), and the next put
hits rcuref_put_slowpath() from dst_release().
Clear res->rt6 when suppressing the route so suppressed lookups fall
through to the null dst instead of reusing the released one.
Products Associated with CVE-2026-74581
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Affected Versions
Linux:- Version 209d35ee34e25f9668c404350a1c86d914c54ffa and below 90c57310e266eb94e4a80d6b15a9ca131d2e82cb is affected.
- Version 8ef8a76a340ebdb2c2eea3f6fb0ebbed09a16383 and below 5d29b286c9de0b309e94b9ed083aa1a2f429434f is affected.
- Version cdef485217d30382f3bf6448c54b4401648fe3f1 and below 354db6243eca59e9d187ffbf8b7955b044ce84dc is affected.
- Version cdef485217d30382f3bf6448c54b4401648fe3f1 and below 6d98c70fe0ba8c7708bfd5b2a5174d2086775daa is affected.
- Version cdef485217d30382f3bf6448c54b4401648fe3f1 and below 9bad152c42b37499162367fe47867411e62fffa3 is affected.
- Version cdef485217d30382f3bf6448c54b4401648fe3f1 and below dc3ab04220667f254f4348572b2a0b3febff89fb is affected.
- Version cdef485217d30382f3bf6448c54b4401648fe3f1 and below a341c091ca0bfae377747b1b59a3bd8ebe18a937 is affected.
- Version cdef485217d30382f3bf6448c54b4401648fe3f1 and below 6aea62e433fe1b586202a5fee8b5807ce635e1d7 is affected.
- Version ee38eb8cf9a7323884c2b8e0adbbeb2192d31e29 is affected.
- Version 5.10.84 and below 5.10.265 is affected.
- Version 5.15.7 and below 5.15.216 is affected.
- Version 5.4.164 and below 5.5 is affected.
- Version 5.16 is affected.
- Before 5.16 is unaffected.
- Version 5.10.265, <= 5.10.* is unaffected.
- Version 5.15.216, <= 5.15.* is unaffected.
- Version 6.1.183, <= 6.1.* is unaffected.
- Version 6.6.151, <= 6.6.* is unaffected.
- Version 6.12.103, <= 6.12.* is unaffected.
- Version 6.18.44, <= 6.18.* is unaffected.
- Version 7.1.8, <= 7.1.* is unaffected.
- Version 7.2, <= * is unaffected.