{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-64451",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-07-19T15:36:31.788Z",
        "datePublished": "2026-07-25T08:51:21.020Z",
        "dateUpdated": "2026-08-17T04:55:55.128Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-08-17T04:55:55.128Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix NULL pointer dereference in func_set_flag()\n\nfunc_set_flag() dereferences tr->current_trace_flags before verifying\nthat the current tracer is actually the function tracer. When the active\ntracer has been switched away from \"function\" (e.g., to \"wakeup_rt\"),\ntr->current_trace_flags can be NULL, leading to a NULL pointer\ndereference and kernel crash.\n\nThe call chain that triggers this is:\n\n  trace_options_write()\n    -> __set_tracer_option()\n      -> trace->set_flag()          /* func_set_flag */\n\nIn func_set_flag(), the first operation is:\n\n  if (!!set == !!(tr->current_trace_flags->val & bit))\n\nThis dereferences tr->current_trace_flags unconditionally. The safety\ncheck that guards against a non-function tracer:\n\n  if (tr->current_trace != &function_trace)\n      return 0;\n\nis placed *after* the dereference, which is too late.\n\nThis was observed with the following crash dump:\n\n  BUG: unable to handle page fault at 0000000000000000\n  RIP: func_set_flag+0xd\n\n  Call Trace:\n   __set_tracer_option+0x27\n   trace_options_write+0x75\n   vfs_write+0x12a\n   ksys_write+0x66\n   do_syscall_64+0x5b\n\n  RIP: ffffffff914c973d  RSP: ff67ec88b01dfdf0  RFLAGS: 00010202\n  RAX: 0000000000000000  RBX: ff3a826e80354580  RCX: 0000000000000001\n  RDX: 0000000000000001  RSI: 0000000000000000  RDI: ffffffff93918080\n\nThe disassembly confirms the fault:\n\n  func_set_flag+0:   mov 0x1f08(%rdi), %rax  ; RAX = tr->current_trace_flags = NULL\n  func_set_flag+13:  mov (%rax), %eax        ; page fault: dereference NULL\n\nAt the time of the crash:\n  tr->current_trace_flags = 0x0 (NULL)\n  tr->current_trace = wakeup_rt_tracer (not function_trace)\n\nThe scenario is that a process opens a function tracer option file (such\nas \"func_stack_trace\"), then the current tracer is switched to another\ntracer (e.g., \"wakeup_rt\"), which sets current_trace_flags to NULL. When\nthe process subsequently writes to the option file, func_set_flag() is\ninvoked and crashes on the NULL dereference.\n\nFix this by moving the current_trace check before the\ncurrent_trace_flags dereference, so that func_set_flag() returns early\nwhen the function tracer is not active."
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "kernel/trace/trace_functions.c"
                    ],
                    "versions": [
                        {
                            "version": "76680d0d2825900f23bf35290ab2b80bdf3a8e4a",
                            "lessThan": "69f17ac132a38974cf1defb480cef6b79d1ab768",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "76680d0d2825900f23bf35290ab2b80bdf3a8e4a",
                            "lessThan": "c3e94604675e3db186111b8942650d86577df9b0",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                },
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "kernel/trace/trace_functions.c"
                    ],
                    "versions": [
                        {
                            "version": "6.19",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "6.19",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.1.4",
                            "lessThanOrEqual": "7.1.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2",
                            "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": "6.19",
                                    "versionEndExcluding": "7.1.4"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.19",
                                    "versionEndExcluding": "7.2"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/69f17ac132a38974cf1defb480cef6b79d1ab768"
                },
                {
                    "url": "https://git.kernel.org/stable/c/c3e94604675e3db186111b8942650d86577df9b0"
                }
            ],
            "title": "tracing: Fix NULL pointer dereference in func_set_flag()",
            "x_generator": {
                "engine": "bippy-1.2.0"
            }
        }
    }
}