CVE-2026-74581 (CVSS 9.8)

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.

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CVSS v3.1 Score

9.8

CRITICAL

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

EPSS — Exploit Prediction

0.0040

Probability of exploitation

0.34%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/354db6243eca59e9d187ffbf8b7955b044ce84dc https://git.kernel.org/stable/c/5d29b286c9de0b309e94b9ed083aa1a2f429434f https://git.kernel.org/stable/c/6aea62e433fe1b586202a5fee8b5807ce635e1d7 https://git.kernel.org/stable/c/6d98c70fe0ba8c7708bfd5b2a5174d2086775daa https://git.kernel.org/stable/c/90c57310e266eb94e4a80d6b15a9ca131d2e82cb https://git.kernel.org/stable/c/9bad152c42b37499162367fe47867411e62fffa3 https://git.kernel.org/stable/c/a341c091ca0bfae377747b1b59a3bd8ebe18a937 https://git.kernel.org/stable/c/dc3ab04220667f254f4348572b2a0b3febff89fb

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. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-74581? +

CVE-2026-74581 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0040, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-74581? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

CVE-2026-74581