SEPTEMBER 17, 2026
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Case File

CVE-2026-74581

CRITICAL · CVSS 9.8 EPSS 0.40%

Source: NVD + CISA KEV + EPSS · Published 2026-08-21 · Last synced 2026-09-17

CyberRota Analysis

AI-Generated

The vulnerability affects the Linux kernel's IPv6 routing functionality, specifically in the handling of suppressed fib6 rules, which can lead to the reuse of a released route. This flaw may allow an attacker to exploit stale routing information, potentially resulting in unauthorized access or denial of service. System administrators and developers managing Linux-based systems should prioritize addressing this issue to mitigate potential security risks.

CVE
CVE-2026-74581
Severity
CRITICAL
CVSS
9.8
EPSS
0.40%
Linux

Original NVD 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.