Remote kernel crash via stale IPv6 route pointer
Published Aug 21, 2026 · Updated Aug 25, 2026
Use-after-free in the Linux kernel's IPv6 FIB rule lookup allows remote attackers to crash hosts via crafted IPv6 traffic. fib6_rule_suppress() releases a suppressed rt6_info through ip6_rt_put_flags() but leaves res->rt6 pointing to it, so a later lookup returns freed memory. The path is remotely reachable only when IPv6 policy routing uses a suppressing rule; reuse followed by dst_release() can crash the kernel.
Summary
What happened
Use-after-free in the Linux kernel's IPv6 FIB rule lookup allows remote attackers to crash hosts via crafted IPv6 traffic. fib6_rule_suppress() releases a suppressed rt6_info through ip6_rt_put_flags() but leaves res->rt6 pointing to it, so a later lookup returns freed memory. The path is remotely reachable only when IPv6 policy routing uses a suppressing rule; reuse followed by dst_release() can crash the kernel.
The record
- CVE
- CVE-2026-74581
- Published
- Aug 21, 2026
- Updated
- Aug 25, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-416, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 21, 2026CVE publishedPublication date reported by the CVE source.
- Aug 25, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=209d35ee34e25f9668c404350a1c86d914c54ffa <90c57310e266eb94e4a80d6b15a9ca131d2e82cb
- Affected versionversion=5.10.84 <5.10.265
- Affected versionversion=5.15.7 <5.15.216
- Affected versionversion=5.16
- Affected versionversion=5.4.164 <5.5
- Affected versionversion=8ef8a76a340ebdb2c2eea3f6fb0ebbed09a16383 <5d29b286c9de0b309e94b9ed083aa1a2f429434f
- Affected versionversion=cdef485217d30382f3bf6448c54b4401648fe3f1 <354db6243eca59e9d187ffbf8b7955b044ce84dc
- Affected versionversion=cdef485217d30382f3bf6448c54b4401648fe3f1 <6aea62e433fe1b586202a5fee8b5807ce635e1d7
- Affected versionversion=cdef485217d30382f3bf6448c54b4401648fe3f1 <6d98c70fe0ba8c7708bfd5b2a5174d2086775daa
- Affected versionversion=cdef485217d30382f3bf6448c54b4401648fe3f1 <9bad152c42b37499162367fe47867411e62fffa3
- Affected versionversion=cdef485217d30382f3bf6448c54b4401648fe3f1 <a341c091ca0bfae377747b1b59a3bd8ebe18a937
- Affected versionversion=cdef485217d30382f3bf6448c54b4401648fe3f1 <dc3ab04220667f254f4348572b2a0b3febff89fb
- Affected versionversion=ee38eb8cf9a7323884c2b8e0adbbeb2192d31e29
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
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