{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-43465", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-01T14:12:56.011Z", "datePublished": "2026-05-08T14:22:26.822Z", "dateUpdated": "2026-08-05T12:28:08.583Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:28:08.583Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/mlx5e: RX, Fix XDP multi-buf frag counting for striding RQ\n\nXDP multi-buf programs can modify the layout of the XDP buffer when the\nprogram calls bpf_xdp_pull_data() or bpf_xdp_adjust_tail(). The\nreferenced commit in the fixes tag corrected the assumption in the mlx5\ndriver that the XDP buffer layout doesn't change during a program\nexecution. However, this fix introduced another issue: the dropped\nfragments still need to be counted on the driver side to avoid page\nfragment reference counting issues.\n\nThe issue was discovered by the drivers/net/xdp.py selftest,\nmore specifically the test_xdp_native_tx_mb:\n- The mlx5 driver allocates a page_pool page and initializes it with\n a frag counter of 64 (pp_ref_count=64) and the internal frag counter\n to 0.\n- The test sends one packet with no payload.\n- On RX (mlx5e_skb_from_cqe_mpwrq_nonlinear()), mlx5 configures the XDP\n buffer with the packet data starting in the first fragment which is the\n page mentioned above.\n- The XDP program runs and calls bpf_xdp_pull_data() which moves the\n header into the linear part of the XDP buffer. As the packet doesn't\n contain more data, the program drops the tail fragment since it no\n longer contains any payload (pp_ref_count=63).\n- mlx5 device skips counting this fragment. Internal frag counter\n remains 0.\n- mlx5 releases all 64 fragments of the page but page pp_ref_count is\n 63 => negative reference counting error.\n\nResulting splat during the test:\n\n WARNING: CPU: 0 PID: 188225 at ./include/net/page_pool/helpers.h:297 mlx5e_page_release_fragmented.isra.0+0xbd/0xe0 [mlx5_core]\n Modules linked in: [...]\n CPU: 0 UID: 0 PID: 188225 Comm: ip Not tainted 6.18.0-rc7_for_upstream_min_debug_2025_12_08_11_44 #1 NONE\n Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014\n RIP: 0010:mlx5e_page_release_fragmented.isra.0+0xbd/0xe0 [mlx5_core]\n [...]\n Call Trace:\n \n mlx5e_free_rx_mpwqe+0x20a/0x250 [mlx5_core]\n mlx5e_dealloc_rx_mpwqe+0x37/0xb0 [mlx5_core]\n mlx5e_free_rx_descs+0x11a/0x170 [mlx5_core]\n mlx5e_close_rq+0x78/0xa0 [mlx5_core]\n mlx5e_close_queues+0x46/0x2a0 [mlx5_core]\n mlx5e_close_channel+0x24/0x90 [mlx5_core]\n mlx5e_close_channels+0x5d/0xf0 [mlx5_core]\n mlx5e_safe_switch_params+0x2ec/0x380 [mlx5_core]\n mlx5e_change_mtu+0x11d/0x490 [mlx5_core]\n mlx5e_change_nic_mtu+0x19/0x30 [mlx5_core]\n netif_set_mtu_ext+0xfc/0x240\n do_setlink.isra.0+0x226/0x1100\n rtnl_newlink+0x7a9/0xba0\n rtnetlink_rcv_msg+0x220/0x3c0\n netlink_rcv_skb+0x4b/0xf0\n netlink_unicast+0x255/0x380\n netlink_sendmsg+0x1f3/0x420\n __sock_sendmsg+0x38/0x60\n ____sys_sendmsg+0x1e8/0x240\n ___sys_sendmsg+0x7c/0xb0\n [...]\n __sys_sendmsg+0x5f/0xb0\n do_syscall_64+0x55/0xc70\n\nThe problem applies for XDP_PASS as well which is handled in a different\ncode path in the driver.\n\nThis patch fixes the issue by doing page frag counting on all the\noriginal XDP buffer fragments for all relevant XDP actions (XDP_TX ,\nXDP_REDIRECT and XDP_PASS). This is basically reverting to the original\ncounting before the commit in the fixes tag.\n\nAs frag_page is still pointing to the original tail, the nr_frags\nparameter to xdp_update_skb_frags_info() needs to be calculated\nin a different way to reflect the new nr_frags." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - The vulnerable mlx5e RX path is reached by received packets on an affected Mellanox interface in a deployment running an XDP multi-buffer program. A remote peer can trigger the fragment-accounting path by sending packets processed by that XDP program.\nAC:L - Once the affected striding RQ and XDP multi-buffer program are in use, triggering only requires packets that cause bpf_xdp_pull_data() or bpf_xdp_adjust_tail() to drop fragments. There is no race or probabilistic condition in the vulnerable path.\nPR:N - The attacker does not need privileges to send the triggering network traffic to a configured affected interface. Loading the XDP program is an environmental precondition for the vulnerable deployment, not an action required from the attacker.\nUI:N - No victim user action is required after the affected interface and XDP program are configured. Packet reception drives the vulnerable path automatically in NAPI RX processing.\nS:U - The impact remains within the same kernel and host security authority. This is not a VM escape, IOMMU bypass, or cross-scope boundary violation.\nC:H - The bug corrupts page-pool fragment lifetime accounting, which can leave pages recycled or referenced incorrectly while packet buffers still point to them. Under the required higher-severity assumption, this memory lifetime corruption can expose kernel or packet memory.\nI:H - Incorrect page-pool reference accounting can cause stale or prematurely recycled packet pages to be reused while still referenced, creating a kernel memory corruption condition. Such lifetime corruption is defensibly treated as high integrity impact.\nA:H - The observed failure is a page_pool refcount underflow warning, and repeated triggering can corrupt RX page accounting, exhaust resources, or panic systems configured with panic_on_warn. This provides high availability impact." } ] } ], "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_rx.c" ], "versions": [ { "version": "87bcef158ac1faca1bd7e0104588e8e2956d10be", "lessThan": "7d7342a18fadcdb70a63b3c930dc63528ce51832", "status": "affected", "versionType": "git" }, { "version": "87bcef158ac1faca1bd7e0104588e8e2956d10be", "lessThan": "043bd62f748bc9fd98154037aa598cffbd3c667c", "status": "affected", "versionType": "git" }, { "version": "87bcef158ac1faca1bd7e0104588e8e2956d10be", "lessThan": "db25c42c2e1f9c0d136420fff5e5700f7e771a6f", "status": "affected", "versionType": "git" }, { "version": "8b051d7f530e8a5237da242fbeafef02fec6b813", "status": "affected", "versionType": "git" }, { "version": "cb9edd583e23979ee546981be963ad5f217e8b18", "status": "affected", "versionType": "git" }, { "version": "f2557d7fa38e9475b38588f5c124476091480f53", "status": "affected", "versionType": "git" }, { "version": "6.6.115", "lessThan": "6.7", "status": "affected", "versionType": "semver" }, { "version": "6.12.56", "lessThan": "6.13", "status": "affected", "versionType": "semver" }, { "version": "6.17.6", "lessThan": "6.18", "status": "affected", "versionType": "semver" } ] }, { "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_rx.c" ], "versions": [ { "version": "6.18", "status": "affected" }, { "version": "0", "lessThan": "6.18", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.19", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.9", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "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": "6.18", "versionEndExcluding": "6.18.19" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18", "versionEndExcluding": "6.19.9" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18", "versionEndExcluding": "7.0" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6.115" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.56" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.17.6" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/7d7342a18fadcdb70a63b3c930dc63528ce51832" }, { "url": "https://git.kernel.org/stable/c/043bd62f748bc9fd98154037aa598cffbd3c667c" }, { "url": "https://git.kernel.org/stable/c/db25c42c2e1f9c0d136420fff5e5700f7e771a6f" } ], "title": "net/mlx5e: RX, Fix XDP multi-buf frag counting for striding RQ", "x_generator": { "engine": "bippy-1.2.0" } } } }