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CVE-2026-74581

CRITICALCVSS 9.8/10EPSS 0.42%

Last modified

CVE-2026-74581 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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.. EPSS estimates a 0.42% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1
9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
0.42%

34.9th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 209d35ee34e25f9668c404350a1c86d914c54ffa, < 90c57310e266eb94e4a80d6b15a9ca131d2e82cb; >= 8ef8a76a340ebdb2c2eea3f6fb0ebbed09a16383, < 5d29b286c9de0b309e94b9ed083aa1a2f429434f; >= cdef485217d30382f3bf6448c54b4401648fe3f1, < 354db6243eca59e9d187ffbf8b7955b044ce84dc; >= cdef485217d30382f3bf6448c54b4401648fe3f1, < 6d98c70fe0ba8c7708bfd5b2a5174d2086775daa; >= cdef485217d30382f3bf6448c54b4401648fe3f1, < 9bad152c42b37499162367fe47867411e62fffa3; >= cdef485217d30382f3bf6448c54b4401648fe3f1, < dc3ab04220667f254f4348572b2a0b3febff89fb; >= cdef485217d30382f3bf6448c54b4401648fe3f1, < a341c091ca0bfae377747b1b59a3bd8ebe18a937; >= cdef485217d30382f3bf6448c54b4401648fe3f1, < 6aea62e433fe1b586202a5fee8b5807ce635e1d7; ee38eb8cf9a7323884c2b8e0adbbeb2192d31e29; >= 5.10.84, < 5.10.265; >= 5.15.7, < 5.15.216; >= 5.4.164, < 5.5
LinuxLinux5.16

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-74581?
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.
How severe is CVE-2026-74581?
CVE-2026-74581 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.42% probability of exploitation in the next 30 days.
How do I fix CVE-2026-74581?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST