net, bpf: fix null-ptr-deref in xdp_master_redirect() for down master_CVE-2026-53069

{
    "lastseen": "",
    "description": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet, bpf: fix null-ptr-deref in xdp_master_redirect() for down master\n\nsyzkaller reported a kernel panic in bond_rr_gen_slave_id() reached via\nxdp_master_redirect(). Full decoded trace:\n\n  https://syzkaller.appspot.com/bug?extid=80e046b8da2820b6ba73\n\nbond_rr_gen_slave_id() dereferences bond->rr_tx_counter, a per-CPU\ncounter that bonding only allocates in bond_open() when the mode is\nround-robin. If the bond device was never brought up, rr_tx_counter\nstays NULL.\n\nThe XDP redirect path can still reach that code on a bond that was\nnever opened: bpf_master_redirect_enabled_key is a global static key,\nso as soon as any bond device has native XDP attached, the\nXDP_TX -> xdp_master_redirect() interception is enabled for every\nslave system-wide. The path xdp_master_redirect() ->\nbond_xdp_get_xmit_slave() -> bond_xdp_xmit_roundrobin_slave_get() ->\nbond_rr_gen_slave_id() then runs against a bond that has no\nrr_tx_counter and crashes.\n\nFix this in the generic xdp_master_redirect() by refusing to call into\nthe master's ->ndo_xdp_get_xmit_slave() when the master device is not\nup. IFF_UP is only set after ->ndo_open() has successfully returned,\nso this reliably excludes masters whose XDP state has not been fully\ninitialized. Drop the frame with XDP_ABORTED so the exception is\nvisible via trace_xdp_exception() rather than silently falling through.\nThis is not specific to bonding: any current or future master that\ndefers XDP state allocation to ->ndo_open() is protected.",
    "published": "2026-06-24T16:30:10.930Z",
    "modified": "2026-06-28T06:38:53.474Z",
    "type": "cve",
    "title": "net, bpf: fix null-ptr-deref in xdp_master_redirect() for down master",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/3128b294b426533c8d9162187446d93a8a160359\nhttps://git.kernel.org/stable/c/acbf45bd584d924b320bee2a7fe2a26f64904d95\nhttps://git.kernel.org/stable/c/866d3d9b87751b1944168fd82615505e0c0fd6cf\nhttps://git.kernel.org/stable/c/183128da0406b1c10e6f60b7b9fe70788b9c8c1d\nhttps://git.kernel.org/stable/c/7bad93e99737e4a5c0c14ac50c05152cf4e28022\nhttps://git.kernel.org/stable/c/ea690b3b6e58ae00979af8195b4cc24df466b65e\nhttps://git.kernel.org/stable/c/1921f91298d1388a0bb9db8f83800c998b649cb3",
    "id": "CVE-2026-53069",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "Linux Linux 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7\nLinux Linux 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7\nLinux Linux 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7\nLinux Linux 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7\nLinux Linux 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7\nLinux Linux 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7\nLinux Linux 879af96ffd72706c6e3278ea6b45b0b0e37ec5d7\nLinux Linux 5.15",
    "sourceHref": "",
    "cvss": {
        "score": 7.5,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
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        "baseScore": 0,
        "baseSeverity": "",
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        "privilegesRequired": "",
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        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
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            "baseScore": 0,
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            "privilegesRequired": "",
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        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Linux",
    "version": "879af96ffd72706c6e3278ea6b45b0b0e37ec5d7",
    "vendor": "Linux",
    "ai_description": "",
    "ai_severity": "",
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    "ai_score": 0
}