{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-43456", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-01T14:12:56.010Z", "datePublished": "2026-05-08T14:22:20.036Z", "dateUpdated": "2026-08-05T12:28:03.247Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:28:03.247Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbonding: fix type confusion in bond_setup_by_slave()\n\nkernel BUG at net/core/skbuff.c:2306!\nOops: invalid opcode: 0000 [#1] SMP KASAN NOPTI\nRIP: 0010:pskb_expand_head+0xa08/0xfe0 net/core/skbuff.c:2306\nRSP: 0018:ffffc90004aff760 EFLAGS: 00010293\nRAX: 0000000000000000 RBX: ffff88807e3c8780 RCX: ffffffff89593e0e\nRDX: ffff88807b7c4900 RSI: ffffffff89594747 RDI: ffff88807b7c4900\nRBP: 0000000000000820 R08: 0000000000000005 R09: 0000000000000000\nR10: 00000000961a63e0 R11: 0000000000000000 R12: ffff88807e3c8780\nR13: 00000000961a6560 R14: dffffc0000000000 R15: 00000000961a63e0\nCS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00007fe1a0ed8df0 CR3: 000000002d816000 CR4: 00000000003526f0\nCall Trace:\n \n ipgre_header+0xdd/0x540 net/ipv4/ip_gre.c:900\n dev_hard_header include/linux/netdevice.h:3439 [inline]\n packet_snd net/packet/af_packet.c:3028 [inline]\n packet_sendmsg+0x3ae5/0x53c0 net/packet/af_packet.c:3108\n sock_sendmsg_nosec net/socket.c:727 [inline]\n __sock_sendmsg net/socket.c:742 [inline]\n ____sys_sendmsg+0xa54/0xc30 net/socket.c:2592\n ___sys_sendmsg+0x190/0x1e0 net/socket.c:2646\n __sys_sendmsg+0x170/0x220 net/socket.c:2678\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\nRIP: 0033:0x7fe1a0e6c1a9\n\nWhen a non-Ethernet device (e.g. GRE tunnel) is enslaved to a bond,\nbond_setup_by_slave() directly copies the slave's header_ops to the\nbond device:\n\n bond_dev->header_ops = slave_dev->header_ops;\n\nThis causes a type confusion when dev_hard_header() is later called\non the bond device. Functions like ipgre_header(), ip6gre_header(),all use\nnetdev_priv(dev) to access their device-specific private data. When\ncalled with the bond device, netdev_priv() returns the bond's private\ndata (struct bonding) instead of the expected type (e.g. struct\nip_tunnel), leading to garbage values being read and kernel crashes.\n\nFix this by introducing bond_header_ops with wrapper functions that\ndelegate to the active slave's header_ops using the slave's own\ndevice. This ensures netdev_priv() in the slave's header functions\nalways receives the correct device.\n\nThe fix is placed in the bonding driver rather than individual device\ndrivers, as the root cause is bond blindly inheriting header_ops from\nthe slave without considering that these callbacks expect a specific\nnetdev_priv() layout.\n\nThe type confusion can be observed by adding a printk in\nipgre_header() and running the following commands:\n\n ip link add dummy0 type dummy\n ip addr add 10.0.0.1/24 dev dummy0\n ip link set dummy0 up\n ip link add gre1 type gre local 10.0.0.1\n ip link add bond1 type bond mode active-backup\n ip link set gre1 master bond1\n ip link set gre1 up\n ip link set bond1 up\n ip addr add fe80::1/64 dev bond1" } ], "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 vulnerable path is reached through local rtnetlink/AF_PACKET operations: creating/enslaving a non-Ethernet slave to a bond and then causing `dev_hard_header()` on the bond device. Remote packets are not sufficient without the vulnerable local device configuration.\nAC:L - No race or special external timing is required; the attacker can deterministically create the bond/GRE setup and trigger the confused header callback. Required modules/configuration are common and autoloadable through rtnetlink in normal deployments.\nPR:L - The setup requires `CAP_NET_ADMIN` and the AF_PACKET trigger requires `CAP_NET_RAW`, but both are obtainable by an unprivileged local user inside a user/network namespace. Therefore this is low privilege rather than real init-namespace root only.\nUI:N - Exploitation does not require a victim user to perform an action. The attacker can perform the setup and trigger locally.\nS:U - The impact is within the kernel security authority on the same system. This is not a VM escape, IOMMU bypass, or cross-authority boundary violation.\nC:H - The bug is kernel type confusion where bonding private data is interpreted as another device's private structure, and the confused callback can read kernel data using the wrong layout. Following the required higher-severity rule for type confusion, confidentiality impact is High.\nI:H - The confused header callback uses bogus private-data fields to construct and push protocol headers into an skb, making this a kernel memory/type confusion condition rather than a pure NULL dereference. Type confusion is scored as High integrity impact.\nA:H - The reported failure is a kernel BUG/oops in `pskb_expand_head()` reachable through the confused `ipgre_header()` call. This provides a reliable local kernel crash/DoS." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/bonding/bond_main.c" ], "versions": [ { "version": "1284cd3a2b740d0118458d2ea470a1e5bc19b187", "lessThan": "5d0fb9806ab6cf2c3cfba0e1b8c701da65e25af8", "status": "affected", "versionType": "git" }, { "version": "1284cd3a2b740d0118458d2ea470a1e5bc19b187", "lessThan": "9baf26a91565b7bb2b1d9f99aaf884a2b28c2f6d", "status": "affected", "versionType": "git" }, { "version": "1284cd3a2b740d0118458d2ea470a1e5bc19b187", "lessThan": "6ac890f1d60ac3707ee8dae15a67d9a833e49956", "status": "affected", "versionType": "git" }, { "version": "1284cd3a2b740d0118458d2ea470a1e5bc19b187", "lessThan": "95597d11dc8bddb2b9a051c9232000bfbb5e43ba", "status": "affected", "versionType": "git" }, { "version": "1284cd3a2b740d0118458d2ea470a1e5bc19b187", "lessThan": "950803f7254721c1c15858fbbfae3deaaeeecb11", "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/bonding/bond_main.c" ], "versions": [ { "version": "2.6.24", "status": "affected" }, { "version": "0", "lessThan": "2.6.24", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.78", "lessThanOrEqual": "6.12.*", "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": "2.6.24", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.24", "versionEndExcluding": "6.12.78" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.24", "versionEndExcluding": "6.18.19" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.24", "versionEndExcluding": "6.19.9" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.24", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/5d0fb9806ab6cf2c3cfba0e1b8c701da65e25af8" }, { "url": "https://git.kernel.org/stable/c/9baf26a91565b7bb2b1d9f99aaf884a2b28c2f6d" }, { "url": "https://git.kernel.org/stable/c/6ac890f1d60ac3707ee8dae15a67d9a833e49956" }, { "url": "https://git.kernel.org/stable/c/95597d11dc8bddb2b9a051c9232000bfbb5e43ba" }, { "url": "https://git.kernel.org/stable/c/950803f7254721c1c15858fbbfae3deaaeeecb11" } ], "title": "bonding: fix type confusion in bond_setup_by_slave()", "x_generator": { "engine": "bippy-1.2.0" } } } }