{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-38440","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-04-16T04:51:24.016Z","datePublished":"2025-07-25T15:27:19.447Z","dateUpdated":"2026-08-05T12:01:56.083Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:01:56.083Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/mlx5e: Fix race between DIM disable and net_dim()\n\nThere's a race between disabling DIM and NAPI callbacks using the dim\npointer on the RQ or SQ.\n\nIf NAPI checks the DIM state bit and sees it still set, it assumes\n`rq->dim` or `sq->dim` is valid. But if DIM gets disabled right after\nthat check, the pointer might already be set to NULL, leading to a NULL\npointer dereference in net_dim().\n\nFix this by calling `synchronize_net()` before freeing the DIM context.\nThis ensures all in-progress NAPI callbacks are finished before the\npointer is cleared.\n\nKernel log:\n\nBUG: kernel NULL pointer dereference, address: 0000000000000000\n...\nRIP: 0010:net_dim+0x23/0x190\n...\nCall Trace:\n <TASK>\n ? __die+0x20/0x60\n ? page_fault_oops+0x150/0x3e0\n ? common_interrupt+0xf/0xa0\n ? sysvec_call_function_single+0xb/0x90\n ? exc_page_fault+0x74/0x130\n ? asm_exc_page_fault+0x22/0x30\n ? net_dim+0x23/0x190\n ? mlx5e_poll_ico_cq+0x41/0x6f0 [mlx5_core]\n ? sysvec_apic_timer_interrupt+0xb/0x90\n mlx5e_handle_rx_dim+0x92/0xd0 [mlx5_core]\n mlx5e_napi_poll+0x2cd/0xac0 [mlx5_core]\n ? mlx5e_poll_ico_cq+0xe5/0x6f0 [mlx5_core]\n busy_poll_stop+0xa2/0x200\n ? mlx5e_napi_poll+0x1d9/0xac0 [mlx5_core]\n ? mlx5e_trigger_irq+0x130/0x130 [mlx5_core]\n __napi_busy_loop+0x345/0x3b0\n ? sysvec_call_function_single+0xb/0x90\n ? asm_sysvec_call_function_single+0x16/0x20\n ? sysvec_apic_timer_interrupt+0xb/0x90\n ? pcpu_free_area+0x1e4/0x2e0\n napi_busy_loop+0x11/0x20\n xsk_recvmsg+0x10c/0x130\n sock_recvmsg+0x44/0x70\n __sys_recvfrom+0xbc/0x130\n ? __schedule+0x398/0x890\n __x64_sys_recvfrom+0x20/0x30\n do_syscall_64+0x4c/0x100\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\n...\n---[ end trace 0000000000000000 ]---\n...\n---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The race is initiated through a local interface — the ethtool coalescing setter (SIOCETHTOOL/ETHTOOL_SCOALESCE or ethtool-netlink COALESCE_SET) toggling adaptive-rx/tx on an mlx5e netdev. Network traffic only drives the NAPI side; the triggering action requires local access to the device's netns.\nAC:L - The attacker controls both sides of the race — repeatedly enabling/disabling DIM while simultaneously keeping NAPI running via traffic or busy-poll recvmsg() — and can retry indefinitely at no cost. No condition beyond the attacker's influence is required.\nPR:L - The path requires CAP_NET_ADMIN only over the network namespace owning the netdev (`ns_capable(net->user_ns, CAP_NET_ADMIN)`), which an unprivileged user obtains in a user namespace (unshare -Urn) that holds an mlx5 netdev such as an SR-IOV VF assigned to a container.\nUI:N - The attacker performs both the ethtool toggle and the traffic generation; no action by any other user or administrator is needed.\nS:U - The corruption and crash are confined to the kernel of the affected host, with no crossing into a different security authority such as a hypervisor or IOMMU boundary.\nC:H - The freed `struct dim` can be dereferenced by in-flight NAPI after `kvfree()`, and a use-after-free on a heap-sprayable slab object lets an attacker overlap it with attacker-chosen data and leverage the resulting corruption for disclosure of kernel memory.\nI:H - `net_dim()` writes into the freed object (`dim->state`, `dim->start_sample`) and calls `schedule_work(&dim->work)` on a freed `work_struct`, giving write and list-manipulation primitives against reclaimed memory that are exploitable for control-flow hijacking.\nA:H - The demonstrated result is a NULL pointer dereference inside `net_dim()` executing in interrupt context, producing \"Fatal exception in interrupt\" and a full kernel panic that the attacker can trigger repeatedly."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ethernet/mellanox/mlx5/core/en_dim.c"],"versions":[{"version":"445a25f6e1a2f6a132b06af6ede4f3c9b5f9af68","lessThan":"7581afc051542e11ccf3ade68acd01b7fb1a3cde","status":"affected","versionType":"git"},{"version":"445a25f6e1a2f6a132b06af6ede4f3c9b5f9af68","lessThan":"2bc6fb90486e42dd80e660ef7a40c02b2516c6d6","status":"affected","versionType":"git"},{"version":"445a25f6e1a2f6a132b06af6ede4f3c9b5f9af68","lessThan":"eb41a264a3a576dc040ee37c3d9d6b7e2d9be968","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ethernet/mellanox/mlx5/core/en_dim.c"],"versions":[{"version":"6.10","status":"affected"},{"version":"0","lessThan":"6.10","status":"unaffected","versionType":"semver"},{"version":"6.12.39","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.15.7","lessThanOrEqual":"6.15.*","status":"unaffected","versionType":"semver"},{"version":"6.16","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.12.39"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.15.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.16"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/7581afc051542e11ccf3ade68acd01b7fb1a3cde"},{"url":"https://git.kernel.org/stable/c/2bc6fb90486e42dd80e660ef7a40c02b2516c6d6"},{"url":"https://git.kernel.org/stable/c/eb41a264a3a576dc040ee37c3d9d6b7e2d9be968"}],"title":"net/mlx5e: Fix race between DIM disable and net_dim()","x_generator":{"engine":"bippy-1.2.0"}}}}