{
    "data_version": "4.0",
    "data_type": "CVE",
    "data_format": "MITRE",
    "CVE_data_meta": {
        "ID": "CVE-2025-21792",
        "ASSIGNER": "cve@kernel.org",
        "STATE": "PUBLIC"
    },
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nax25: Fix refcount leak caused by setting SO_BINDTODEVICE sockopt\n\nIf an AX25 device is bound to a socket by setting the SO_BINDTODEVICE\nsocket option, a refcount leak will occur in ax25_release().\n\nCommit 9fd75b66b8f6 (\"ax25: Fix refcount leaks caused by ax25_cb_del()\")\nadded decrement of device refcounts in ax25_release(). In order for that\nto work correctly the refcounts must already be incremented when the\ndevice is bound to the socket. An AX25 device can be bound to a socket\nby either calling ax25_bind() or setting SO_BINDTODEVICE socket option.\nIn both cases the refcounts should be incremented, but in fact it is done\nonly in ax25_bind().\n\nThis bug leads to the following issue reported by Syzkaller:\n\n================================================================\nrefcount_t: decrement hit 0; leaking memory.\nWARNING: CPU: 1 PID: 5932 at lib/refcount.c:31 refcount_warn_saturate+0x1ed/0x210 lib/refcount.c:31\nModules linked in:\nCPU: 1 UID: 0 PID: 5932 Comm: syz-executor424 Not tainted 6.13.0-rc4-syzkaller-00110-g4099a71718b0 #0\nHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014\nRIP: 0010:refcount_warn_saturate+0x1ed/0x210 lib/refcount.c:31\nCall Trace:\n <TASK>\n __refcount_dec include/linux/refcount.h:336 [inline]\n refcount_dec include/linux/refcount.h:351 [inline]\n ref_tracker_free+0x710/0x820 lib/ref_tracker.c:236\n netdev_tracker_free include/linux/netdevice.h:4156 [inline]\n netdev_put include/linux/netdevice.h:4173 [inline]\n netdev_put include/linux/netdevice.h:4169 [inline]\n ax25_release+0x33f/0xa10 net/ax25/af_ax25.c:1069\n __sock_release+0xb0/0x270 net/socket.c:640\n sock_close+0x1c/0x30 net/socket.c:1408\n ...\n do_syscall_x64 arch/x86/entry/common.c:52 [inline]\n do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n ...\n </TASK>\n================================================================\n\nFix the implementation of ax25_setsockopt() by adding increment of\nrefcounts for the new device bound, and decrement of refcounts for\nthe old unbound device."
            }
        ]
    },
    "problemtype": {
        "problemtype_data": [
            {
                "description": [
                    {
                        "lang": "eng",
                        "value": "n/a"
                    }
                ]
            }
        ]
    },
    "affects": {
        "vendor": {
            "vendor_data": [
                {
                    "vendor_name": "Linux",
                    "product": {
                        "product_data": [
                            {
                                "product_name": "Linux",
                                "version": {
                                    "version_data": [
                                        {
                                            "version_affected": "<",
                                            "version_name": "9fd75b66b8f68498454d685dc4ba13192ae069b0",
                                            "version_value": "90056ece99966182dc0e367f3fd2afab46ada847"
                                        },
                                        {
                                            "version_value": "not down converted",
                                            "x_cve_json_5_version_data": {
                                                "versions": [
                                                    {
                                                        "version": "5.18",
                                                        "status": "affected"
                                                    },
                                                    {
                                                        "version": "0",
                                                        "lessThan": "5.18",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
                                                    },
                                                    {
                                                        "version": "6.1.129",
                                                        "lessThanOrEqual": "6.1.*",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
                                                    },
                                                    {
                                                        "version": "6.6.79",
                                                        "lessThanOrEqual": "6.6.*",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
                                                    },
                                                    {
                                                        "version": "6.12.16",
                                                        "lessThanOrEqual": "6.12.*",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
                                                    },
                                                    {
                                                        "version": "6.13.4",
                                                        "lessThanOrEqual": "6.13.*",
                                                        "status": "unaffected",
                                                        "versionType": "semver"
                                                    },
                                                    {
                                                        "version": "6.14-rc3",
                                                        "lessThanOrEqual": "*",
                                                        "status": "unaffected",
                                                        "versionType": "original_commit_for_fix"
                                                    }
                                                ],
                                                "defaultStatus": "affected"
                                            }
                                        }
                                    ]
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                            }
                        ]
                    }
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            ]
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    },
    "references": {
        "reference_data": [
            {
                "url": "https://git.kernel.org/stable/c/90056ece99966182dc0e367f3fd2afab46ada847",
                "refsource": "MISC",
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                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/94a0de224ed52eb2ecd4f4cb1b937b674c9fb955"
            },
            {
                "url": "https://git.kernel.org/stable/c/b58f7ca86a7b8e480c06e30c5163c5d2f4e24023",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/b58f7ca86a7b8e480c06e30c5163c5d2f4e24023"
            },
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                "url": "https://git.kernel.org/stable/c/470bda72fda0fcf54300466d70ce2de62f7835d2",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/470bda72fda0fcf54300466d70ce2de62f7835d2"
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            {
                "url": "https://git.kernel.org/stable/c/bca0902e61731a75fc4860c8720168d9f1bae3b6",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/bca0902e61731a75fc4860c8720168d9f1bae3b6"
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