{"id":"CVE-2026-74465","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-74465","summary":"net: openvswitch: fix potential UAF on meter attach failure","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: openvswitch: fix potential UAF on meter attach failure\n\nWhile attaching a newly created meter attach_meter() function makes\nthe new meter visible to other CPUs but can still fail afterwards.\nOn failure, it detaches the meter back and returns an error.\n\nHowever, this is an unexpected behavior for the ovs_meter_cmd_set()\nthat uses a plain kfree(meter) on attach failure without waiting for\nRCU readers to stop using it, assuming it was never visible.\n\nThis is never a problem for ovs-vswitchd as it always creates meters\nbefore creating any flows that use them.  But the UAF can be triggered\nwith a custom application using uAPI:\n\n BUG: KASAN: slab-use-after-free in ovs_meter_execute (net/openvswitch/meter.c:653)\n Read of size 8 at addr ffff88810d152650 by task meter/2508\n\n Call Trace:\n  ovs_meter_execute (net/openvswitch/meter.c:653)\n  do_execute_actions (net/openvswitch/actions.c:1407)\n  ovs_execute_actions (net/openvswitch/actions.c:1584)\n  ovs_packet_cmd_execute (net/openvswitch/datapath.c:703)\n  ...\n  netlink_sendmsg (af_netlink.c:1900)\n\n Allocated by task 2519:\n  __kasan_kmalloc (mm/kasan/common.c:398 mm/kasan/common.c:415)\n  ovs_meter_cmd_set (net/openvswitch/meter.c:422)\n  ...\n  netlink_sendmsg (af_netlink.c:1900)\n\n Freed by task 2519:\n  kfree (mm/slub.c:2705 mm/slub.c:6405 mm/slub.c:6720)\n  ovs_meter_cmd_set (net/openvswitch/meter.c:479)\n  ...\n  netlink_sendmsg (af_netlink.c:1900)\n\nFix that by making sure attach_meter() doesn't make the meter visible\nuntil all the checks are done and the function can't fail anymore.\n\nThis also makes sure the \"hash\" value is calculated after the potential\nre-sizing of the table.\n\nReported by Trend Micro's Zero Day Initiative as ZDI-CAN-31642.","published":"2026-08-15T12:27:04.403Z","modified":"2026-08-18T03:56:49.053457811Z","cvss":{"score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"6.6.151"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0310d1fa7f9debd0d89629e9f14c7975a47eaa9a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/431a295d93f76fbdb6a7cfce92a9e3dfee1e5d61"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4d03e5fa3fbb1df15258a1eb3d6963f0d65659b3"},{"type":"WEB","url":"https://git.kernel.org/stable/c/90623c9499627803ef3f04fa25a3199402d4fb95"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a58a2b0ce354df531ebc71fc870058c2feb59f6b"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74465.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74465"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-18T03:56:49.053457811Z"}}