{"cve":"CVE-2025-37786","nvd":{"published":"2025-05-01T14:15:42.890","modified":"2026-06-17T09:15:26.267","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: dsa: free routing table on probe failure\n\nIf complete = true in dsa_tree_setup(), it means that we are the last\nswitch of the tree which is successfully probing, and we should be\nsetting up all switches from our probe path.\n\nAfter \"complete\" becomes true, dsa_tree_setup_cpu_ports() or any\nsubsequent function may fail. If that happens, the entire tree setup is\nin limbo: the first N-1 switches have successfully finished probing\n(doing nothing but having allocated persistent memory in the tree's\ndst->ports, and maybe dst->rtable), and switch N failed to probe, ending\nthe tree setup process before anything is tangible from the user's PoV.\n\nIf switch N fails to probe, its memory (ports) will be freed and removed\nfrom dst->ports. However, the dst->rtable elements pointing to its ports,\nas created by dsa_link_touch(), will remain there, and will lead to\nuse-after-free if dereferenced.\n\nIf dsa_tree_setup_switches() returns -EPROBE_DEFER, which is entirely\npossible because that is where ds->ops->setup() is, we get a kasan\nreport like this:\n\n==================================================================\nBUG: KASAN: slab-use-after-free in mv88e6xxx_setup_upstream_port+0x240/0x568\nRead of size 8 at addr ffff000004f56020 by task kworker/u8:3/42\n\nCall trace:\n __asan_report_load8_noabort+0x20/0x30\n mv88e6xxx_setup_upstream_port+0x240/0x568\n mv88e6xxx_setup+0xebc/0x1eb0\n dsa_register_switch+0x1af4/0x2ae0\n mv88e6xxx_register_switch+0x1b8/0x2a8\n mv88e6xxx_probe+0xc4c/0xf60\n mdio_probe+0x78/0xb8\n really_probe+0x2b8/0x5a8\n __driver_probe_device+0x164/0x298\n driver_probe_device+0x78/0x258\n __device_attach_driver+0x274/0x350\n\nAllocated by task 42:\n __kasan_kmalloc+0x84/0xa0\n __kmalloc_cache_noprof+0x298/0x490\n dsa_switch_touch_ports+0x174/0x3d8\n dsa_register_switch+0x800/0x2ae0\n mv88e6xxx_register_switch+0x1b8/0x2a8\n mv88e6xxx_probe+0xc4c/0xf60\n mdio_probe+0x78/0xb8\n really_probe+0x2b8/0x5a8\n __driver_probe_device+0x164/0x298\n driver_probe_device+0x78/0x258\n __device_attach_driver+0x274/0x350\n\nFreed by task 42:\n __kasan_slab_free+0x48/0x68\n kfree+0x138/0x418\n dsa_register_switch+0x2694/0x2ae0\n mv88e6xxx_register_switch+0x1b8/0x2a8\n mv88e6xxx_probe+0xc4c/0xf60\n mdio_probe+0x78/0xb8\n really_probe+0x2b8/0x5a8\n __driver_probe_device+0x164/0x298\n driver_probe_device+0x78/0x258\n __device_attach_driver+0x274/0x350\n\nThe simplest way to fix the bug is to delete the routing table in its\nentirety. dsa_tree_setup_routing_table() has no problem in regenerating\nit even if we deleted links between ports other than those of switch N,\nbecause dsa_link_touch() first checks whether the port pair already\nexists in dst->rtable, allocating if not.\n\nThe deletion of the routing table in its entirety already exists in\ndsa_tree_teardown(), so refactor that into a function that can also be\ncalled from the tree setup error path.\n\nIn my analysis of the commit to blame, it is the one which added\ndsa_link elements to dst->rtable. Prior to that, each switch had its own\nds->rtable which is freed when the switch fails to probe. But the tree\nis potentially persistent memory.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":["CWE-416"],"references":["https://git.kernel.org/stable/c/51df5513cca6349d0bea01bab95cd96cf869976e","https://git.kernel.org/stable/c/5c8066fbdb9653c6e9a224bdcd8f9c91a484f0de","https://git.kernel.org/stable/c/6c20894d21600ca1e8549086dfbb986e277bf8a6","https://git.kernel.org/stable/c/8bf108d7161ffc6880ad13a0cc109de3cf631727","https://git.kernel.org/stable/c/a038f5f15af455dfe35bc68549e02b950978700a"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:01:11.054312287+00:00"},"epss":{"cve":"CVE-2025-37786","score":0.00194,"percentile":0.09095,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}