{"id":"CVE-2026-64580","published":"2026-08-05T08:16:38.027","lastModified":"2026-08-08T15:16:32.950","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm6: clear dst.dev on error to avoid double netdev_put in xfrm6_fill_dst()\n\nOn the error path where in6_dev_get(dev) returns NULL, xfrm6_fill_dst()\nreleases the device reference with netdev_put() but leaves\nxdst->u.dst.dev set. dst_destroy() later calls netdev_put(dst->dev)\nagain, so the same net_device reference is released twice, underflowing\nits refcount (ref_tracker WARNING + \"unregister_netdevice: waiting for\n<dev> to become free\").\n\nClear xdst->u.dst.dev after the netdev_put(), the same way the XFRM\ndevice-offload paths xfrm_dev_state_add() and xfrm_dev_policy_add() in\nnet/xfrm/xfrm_device.c NULL ->dev when releasing the reference on error.\n\n  ref_tracker: reference already released.\n  ref_tracker: allocated in:\n   xfrm6_fill_dst (net/ipv6/xfrm6_policy.c:86)\n   ...\n   udpv6_sendmsg (net/ipv6/udp.c:1696)\n   ...\n  ref_tracker: freed in:\n   xfrm6_fill_dst (net/ipv6/xfrm6_policy.c:90)\n   ...\n  WARNING: lib/ref_tracker.c:322 at ref_tracker_free+0x58b/0x780\n   dst_destroy (net/core/dst.c:115)\n   rcu_core\n   handle_softirqs\n   ...","cvssScore":7.8,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/136992de9bb91871084ae52d172610541c76e4d2","tags":[]},{"url":"https://git.kernel.org/stable/c/43de8a49335e611adb271bbd52e84dfbc11fc185","tags":[]},{"url":"https://git.kernel.org/stable/c/df6856c2dda9187601d29b5fbd7a81b3b178cedf","tags":[]},{"url":"https://git.kernel.org/stable/c/e078da1b4e11390cff3201c19a9a1fe70c5b934f","tags":[]},{"url":"https://git.kernel.org/stable/c/ff636d7b7cba6dea82ecf580415ea57f2c1a11b6","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":{"summary":"The vulnerability in xfrm6_fill_dst() allows for a double netdev_put(), potentially leading to a use-after-free condition and refcount underflow.","exploitability":"Exploitation requires specific error conditions during packet processing, making it moderately difficult but feasible with precise attack vectors.","blast_radius":"If exploited, this could lead to denial of service or arbitrary code execution on affected systems handling IPv6 packets.","remediation":"Apply the patch that clears xdst->u.dst.dev after netdev_put() in xfrm6_fill_dst().","tags":["dos","kernel","ipv6"],"model":"qwen2.5:7b-instruct","analyzedAt":"2026-08-11T06:52:31.851Z"}}