{ "schema_version": "1.6.1", "id": "RPI-CVE-2026-72072", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2026-72072" ], "published": "2026-08-15T06:04:33Z", "summary": "net/mlx5e: macsec: fix use-after-free of metadata_dst on RX SC delete", "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/mlx5e: macsec: fix use-after-free of metadata_dst on RX SC delete\n\nWhen an offloaded MACsec RX SC is deleted, macsec_del_rxsc_ctx() freed\nthe per-SC metadata_dst with metadata_dst_free(), which kfree()s the\nobject unconditionally and ignores the dst reference count. The RX\ndatapath in mlx5e_macsec_offload_handle_rx_skb() looks up the SC under\nrcu_read_lock() via xa_load(), takes a reference with dst_hold() and\nattaches the dst to the skb with skb_dst_set(). A reader that already\nobtained the rx_sc pointer can race with the delete path and operate on\nfreed memory.\n\nFix the owner side by dropping the reference with dst_release() instead\nof freeing unconditionally, and convert the RX datapath to\ndst_hold_safe() so a reader racing the SC delete cannot attach a dst\nwhose last reference was just dropped; only attach it when a reference\nwas actually taken.\n\nmlx5e_macsec_add_rxsc() also published sc_xarray_element via xa_alloc()\nbefore rx_sc->md_dst was allocated and initialised, so a datapath reader\nthat looked the SC up by fs_id could observe rx_sc with md_dst still\nNULL or, on weakly-ordered architectures, a non-NULL md_dst pointer\nwhose contents were not yet visible. NULL-check the xa_load() result and\nmd_dst on the datapath, and reorder add_rxsc() so the xa_alloc() publish\nhappens only after md_dst is fully initialised; the xarray RCU publish\nthen pairs with the rcu_read_lock()/xa_load() in the datapath.\n\nNote: macsec_del_rxsc_ctx() also kfree()s rx_sc->sc_xarray_element\nwithout an RCU grace period while the same datapath reads it under\nrcu_read_lock(); that is a separate pre-existing issue left to a\nfollow-up patch.\n\nFound by 0sec automated security-research tooling (https://0sec.ai).", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.1.47-1+rpt4" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.1.0-rpi3-rpi-2712", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v6", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v8", "binary_version": "1:6.1.47-1+rpt4" } ] }, "database_specific": { "per_version": { "1:6.1.47-1+rpt4": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.178", "compiled_filter": false } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2026-72072" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/b1a4d0c568bbb52c7c04f4fce3c097dae89ed6cb" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/218cc15a4c907659ad4b0e68c535c61594311205" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/4a5073b7b30243658f58b2d2d35a823da7fd34d9" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/ed3cc4218070d6b98bf5fb456dccae424fd38c4f" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/088873af13590ebde10de2ade847f57a05ec61c6" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/de74d8fd10291763d97b218f09adcc7513c975e4" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-08-17T05:50:24Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 7.8, "cvss_v3_severity": "High", "scenario": "AV:L - The UAF is reached by racing MACSEC_CMD_DEL_RXSC/ADD_RXSC netlink configuration (GENL_ADMIN_PERM) against mlx5e MACsec RX processing; the privileged genlink/rtnl control path is required to trigger the bug, not remote packets alone.\nAC:L - An attacker with CAP_NET_ADMIN can drive both sides by looping RX SC add/delete while flooding MACsec-offloaded RX traffic on the mlx5e netdev, reliably winning the RCU race between xa_load/dst_hold and metadata_dst_free.\nPR:L - MACsec offload mutations require GENL_ADMIN_PERM (CAP_NET_ADMIN); on Mellanox ConnectX/BlueField systems this is reachable by cloud tenants with SR-IOV VFs, containers, or user/network namespaces without init-namespace root.\nUI:N - No victim user action is needed; automated concurrent netlink MACsec operations and incoming MACsec-offloaded frames on an active mlx5e interface suffice once MACsec offload is configured.\nS:U - Impact is kernel heap use-after-free and memory corruption within the host kernel on the mlx5 NIC; it enables local privilege escalation but does not by itself cross VM, IOMMU, or hypervisor security boundaries.\nC:H - The race calls dst_hold() and skb_dst_set() on a freed metadata_dst, a classic slab UAF that can disclose kernel memory through subsequent dst_entry and MACsec skb metadata handling.\nI:H - Freed metadata_dst objects can be reallocated via heap spraying while the RX datapath still references them, enabling refcount corruption and arbitrary kernel memory writes or control-flow hijack beyond a mere crash.\nA:H - Concurrent use of freed md_dst during mlx5e MACsec RX processing can cause immediate kernel oops, BUG, or panic on datacenter/cloud hosts using mlx5 hardware MACsec offload, fully denying system availability." } } }