{"id":"CVE-2026-43464","state":"PUBLISHED","title":"net/mlx5e: RX, Fix XDP multi-buf frag counting for legacy RQ","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/mlx5e: RX, Fix XDP multi-buf frag counting for legacy 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\nSuch issue can be observed with the\ntest_xdp_native_adjst_tail_shrnk_data selftest when using a payload of\n3600 and shrinking by 256 bytes (an upcoming selftest patch): the last\nfragment gets released by the XDP code but doesn't get tracked by the\ndriver. This results in a negative pp_ref_count during page release and\nthe following splat:\n\n  WARNING: include/net/page_pool/helpers.h:297 at mlx5e_page_release_fragmented.isra.0+0x4a/0x50 [mlx5_core], CPU#12: ip/3137\n  Modules linked in: [...]\n  CPU: 12 UID: 0 PID: 3137 Comm: ip Not tainted 6.19.0-rc3+ #12 NONE\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014\n  RIP: 0010:mlx5e_page_release_fragmented.isra.0+0x4a/0x50 [mlx5_core]\n  [...]\n  Call Trace:\n   <TASK>\n   mlx5e_dealloc_rx_wqe+0xcb/0x1a0 [mlx5_core]\n   mlx5e_free_rx_descs+0x7f/0x110 [mlx5_core]\n   mlx5e_close_rq+0x50/0x60 [mlx5_core]\n   mlx5e_close_queues+0x36/0x2c0 [mlx5_core]\n   mlx5e_close_channel+0x1c/0x50 [mlx5_core]\n   mlx5e_close_channels+0x45/0x80 [mlx5_core]\n   mlx5e_safe_switch_params+0x1a5/0x230 [mlx5_core]\n   mlx5e_change_mtu+0xf3/0x2f0 [mlx5_core]\n   netif_set_mtu_ext+0xf1/0x230\n   do_setlink.isra.0+0x219/0x1180\n   rtnl_newlink+0x79f/0xb60\n   rtnetlink_rcv_msg+0x213/0x3a0\n   netlink_rcv_skb+0x48/0xf0\n   netlink_unicast+0x24a/0x350\n   netlink_sendmsg+0x1ee/0x410\n   __sock_sendmsg+0x38/0x60\n   ____sys_sendmsg+0x232/0x280\n   ___sys_sendmsg+0x78/0xb0\n   __sys_sendmsg+0x5f/0xb0\n   [...]\n   do_syscall_64+0x57/0xc50\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.","publishedAt":"2026-05-08T14:22:26.039Z","updatedAt":"2026-10-21T12:40:49.291Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"72328f25755ee966724f46e3a0e8e59bef2091ba","status":"affected","lessThan":"1106412414dc3ee62999115be10ca83199b02108","versionType":"git"},{"version":"0049fd63881505566824e88cfa624638f921c808","status":"affected","lessThan":"9488ee96b4f53d2aed474c744f0ed64f61d1dcc9","versionType":"git"},{"version":"afd5ba577c10639f62e8120df67dc70ea4b61176","status":"affected","lessThan":"c74557495efb4bd0adefdfc8678ecdbc82a06da3","versionType":"git"},{"version":"afd5ba577c10639f62e8120df67dc70ea4b61176","status":"affected","lessThan":"03cb50e5b74fce8bf6d92b860371b66253cf0f8d","versionType":"git"},{"version":"afd5ba577c10639f62e8120df67dc70ea4b61176","status":"affected","lessThan":"a6413e6f6c9d9bb9833324cb3753582f7bc0f2fa","versionType":"git"},{"version":"d969645b9b7810289bf3c353ea06957373756b8e","status":"affected","versionType":"git"},{"version":"6.6.115","status":"affected","lessThan":"6.6.160","versionType":"semver"},{"version":"6.12.56","status":"affected","lessThan":"6.12.114","versionType":"semver"},{"version":"6.17.6","status":"affected","lessThan":"6.18","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ethernet/mellanox/mlx5/core/en_rx.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.18","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.19","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.9","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ethernet/mellanox/mlx5/core/en_rx.c"]}],"references":["https://git.kernel.org/stable/c/1106412414dc3ee62999115be10ca83199b02108","https://git.kernel.org/stable/c/9488ee96b4f53d2aed474c744f0ed64f61d1dcc9","https://git.kernel.org/stable/c/c74557495efb4bd0adefdfc8678ecdbc82a06da3","https://git.kernel.org/stable/c/03cb50e5b74fce8bf6d92b860371b66253cf0f8d","https://git.kernel.org/stable/c/a6413e6f6c9d9bb9833324cb3753582f7bc0f2fa"],"weaknesses":[],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/43xxx/CVE-2026-43464.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-43464","state":"PUBLISHED","datePublished":"2026-05-08T14:22:26.039Z","dateUpdated":"2026-10-21T12:40:49.291Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-05-01T14:12:56.011Z"},"containers":{"cna":{"title":"net/mlx5e: RX, Fix XDP multi-buf frag counting for legacy RQ","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 legacy 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\nSuch issue can be observed with the\ntest_xdp_native_adjst_tail_shrnk_data selftest when using a payload of\n3600 and shrinking by 256 bytes (an upcoming selftest patch): the last\nfragment gets released by the XDP code but doesn't get tracked by the\ndriver. This results in a negative pp_ref_count during page release and\nthe following splat:\n\n  WARNING: include/net/page_pool/helpers.h:297 at mlx5e_page_release_fragmented.isra.0+0x4a/0x50 [mlx5_core], CPU#12: ip/3137\n  Modules linked in: [...]\n  CPU: 12 UID: 0 PID: 3137 Comm: ip Not tainted 6.19.0-rc3+ #12 NONE\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014\n  RIP: 0010:mlx5e_page_release_fragmented.isra.0+0x4a/0x50 [mlx5_core]\n  [...]\n  Call Trace:\n   <TASK>\n   mlx5e_dealloc_rx_wqe+0xcb/0x1a0 [mlx5_core]\n   mlx5e_free_rx_descs+0x7f/0x110 [mlx5_core]\n   mlx5e_close_rq+0x50/0x60 [mlx5_core]\n   mlx5e_close_queues+0x36/0x2c0 [mlx5_core]\n   mlx5e_close_channel+0x1c/0x50 [mlx5_core]\n   mlx5e_close_channels+0x45/0x80 [mlx5_core]\n   mlx5e_safe_switch_params+0x1a5/0x230 [mlx5_core]\n   mlx5e_change_mtu+0xf3/0x2f0 [mlx5_core]\n   netif_set_mtu_ext+0xf1/0x230\n   do_setlink.isra.0+0x219/0x1180\n   rtnl_newlink+0x79f/0xb60\n   rtnetlink_rcv_msg+0x213/0x3a0\n   netlink_rcv_skb+0x48/0xf0\n   netlink_unicast+0x24a/0x350\n   netlink_sendmsg+0x1ee/0x410\n   __sock_sendmsg+0x38/0x60\n   ____sys_sendmsg+0x232/0x280\n   ___sys_sendmsg+0x78/0xb0\n   __sys_sendmsg+0x5f/0xb0\n   [...]\n   do_syscall_64+0x57/0xc50\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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"72328f25755ee966724f46e3a0e8e59bef2091ba","status":"affected","lessThan":"1106412414dc3ee62999115be10ca83199b02108","versionType":"git"},{"version":"0049fd63881505566824e88cfa624638f921c808","status":"affected","lessThan":"9488ee96b4f53d2aed474c744f0ed64f61d1dcc9","versionType":"git"},{"version":"afd5ba577c10639f62e8120df67dc70ea4b61176","status":"affected","lessThan":"c74557495efb4bd0adefdfc8678ecdbc82a06da3","versionType":"git"},{"version":"afd5ba577c10639f62e8120df67dc70ea4b61176","status":"affected","lessThan":"03cb50e5b74fce8bf6d92b860371b66253cf0f8d","versionType":"git"},{"version":"afd5ba577c10639f62e8120df67dc70ea4b61176","status":"affected","lessThan":"a6413e6f6c9d9bb9833324cb3753582f7bc0f2fa","versionType":"git"},{"version":"d969645b9b7810289bf3c353ea06957373756b8e","status":"affected","versionType":"git"},{"version":"6.6.115","status":"affected","lessThan":"6.6.160","versionType":"semver"},{"version":"6.12.56","status":"affected","lessThan":"6.12.114","versionType":"semver"},{"version":"6.17.6","status":"affected","lessThan":"6.18","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ethernet/mellanox/mlx5/core/en_rx.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.18","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.19","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.9","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ethernet/mellanox/mlx5/core/en_rx.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/1106412414dc3ee62999115be10ca83199b02108"},{"url":"https://git.kernel.org/stable/c/9488ee96b4f53d2aed474c744f0ed64f61d1dcc9"},{"url":"https://git.kernel.org/stable/c/c74557495efb4bd0adefdfc8678ecdbc82a06da3"},{"url":"https://git.kernel.org/stable/c/03cb50e5b74fce8bf6d92b860371b66253cf0f8d"},{"url":"https://git.kernel.org/stable/c/a6413e6f6c9d9bb9833324cb3753582f7bc0f2fa"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - The vulnerable mlx5e RX path is reached by packets received on a Mellanox Ethernet interface, before any network-layer authentication. A remote peer can supply the packet sizes and traffic needed to enter the multi-buffer receive path.\nAC:L - Once an affected deployment has an XDP multi-buffer program using layout-changing helpers, triggering only requires sending packets that span fragments and cause the program to shrink or pull data. The packet pattern is attacker-controlled and no race or hard-to-hit timing condition is required.\nPR:N - The attacker does not need local privileges or credentials to send packets to the affected interface. Attaching the XDP program is a deployment precondition, but the vulnerable receive path itself is unauthenticated packet processing.\nUI:N - No victim user action is needed after the affected interface and XDP program are in service. Packet reception alone drives the vulnerable code.\nS:U - The bug corrupts accounting inside the same kernel/network-device security authority. It does not cross a VM, IOMMU, or other separate security boundary.\nC:N - The investigated bug is a page-pool fragment reference accounting undercount that leads to negative reference counts and warnings, not an exposed arbitrary read or bounded information leak. The fixed code corrects lifetime accounting rather than a data disclosure path.\nI:N - The issue does not provide a demonstrated primitive for attacker-controlled data modification or control-flow hijack. The corruption is limited to page-pool reference accounting for receive buffers.\nA:H - The malformed accounting triggers WARN_ON splats in page_pool release and can be driven repeatedly through received traffic followed by normal queue teardown or reconfiguration. In severe reasonable deployments, including systems with panic_on_warn or exhausted RX page-pool resources, this can cause a kernel-level denial of service."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-21T12:40:49.291Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.115","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12.56","versionEndExcluding":"6.12.114"},{"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":"6.17.6"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}