{"id":"AZL-56414","summary":"CVE-2025-21682 affecting package kernel 5.15.200.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\neth: bnxt: always recalculate features after XDP clearing, fix null-deref\n\nRecalculate features when XDP is detached.\n\nBefore:\n  # ip li set dev eth0 xdp obj xdp_dummy.bpf.o sec xdp\n  # ip li set dev eth0 xdp off\n  # ethtool -k eth0 | grep gro\n  rx-gro-hw: off [requested on]\n\nAfter:\n  # ip li set dev eth0 xdp obj xdp_dummy.bpf.o sec xdp\n  # ip li set dev eth0 xdp off\n  # ethtool -k eth0 | grep gro\n  rx-gro-hw: on\n\nThe fact that HW-GRO doesn't get re-enabled automatically is just\na minor annoyance. The real issue is that the features will randomly\ncome back during another reconfiguration which just happens to invoke\nnetdev_update_features(). The driver doesn't handle reconfiguring\ntwo things at a time very robustly.\n\nStarting with commit 98ba1d931f61 (\"bnxt_en: Fix RSS logic in\n__bnxt_reserve_rings()\") we only reconfigure the RSS hash table\nif the \"effective\" number of Rx rings has changed. If HW-GRO is\nenabled \"effective\" number of rings is 2x what user sees.\nSo if we are in the bad state, with HW-GRO re-enablement \"pending\"\nafter XDP off, and we lower the rings by / 2 - the HW-GRO rings\ndoing 2x and the ethtool -L doing / 2 may cancel each other out,\nand the:\n\n  if (old_rx_rings != bp-\u003ehw_resc.resv_rx_rings &&\n\ncondition in __bnxt_reserve_rings() will be false.\nThe RSS map won't get updated, and we'll crash with:\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000168\n  RIP: 0010:__bnxt_hwrm_vnic_set_rss+0x13a/0x1a0\n    bnxt_hwrm_vnic_rss_cfg_p5+0x47/0x180\n    __bnxt_setup_vnic_p5+0x58/0x110\n    bnxt_init_nic+0xb72/0xf50\n    __bnxt_open_nic+0x40d/0xab0\n    bnxt_open_nic+0x2b/0x60\n    ethtool_set_channels+0x18c/0x1d0\n\nAs we try to access a freed ring.\n\nThe issue is present since XDP support was added, really, but\nprior to commit 98ba1d931f61 (\"bnxt_en: Fix RSS logic in\n__bnxt_reserve_rings()\") it wasn't causing major issues.","modified":"2026-04-01T05:18:54.021780Z","published":"2025-01-31T12:15:29Z","upstream":["CVE-2025-21682"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-21682"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:2","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"5.15.200.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-56414.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}