{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-45949",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-05-13T15:03:33.088Z",
        "datePublished": "2026-05-27T12:18:05.718Z",
        "dateUpdated": "2026-05-27T12:18:05.718Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-05-27T12:18:05.718Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nhwrng: core - use RCU and work_struct to fix race condition\n\nCurrently, hwrng_fill is not cleared until the hwrng_fillfn() thread\nexits. Since hwrng_unregister() reads hwrng_fill outside the rng_mutex\nlock, a concurrent hwrng_unregister() may call kthread_stop() again on\nthe same task.\n\nAdditionally, if hwrng_unregister() is called immediately after\nhwrng_register(), the stopped thread may have never been executed. Thus,\nhwrng_fill remains dirty even after hwrng_unregister() returns. In this\ncase, subsequent calls to hwrng_register() will fail to start new\nthreads, and hwrng_unregister() will call kthread_stop() on the same\nfreed task. In both cases, a use-after-free occurs:\n\nrefcount_t: addition on 0; use-after-free.\nWARNING: ... at lib/refcount.c:25 refcount_warn_saturate+0xec/0x1c0\nCall Trace:\n kthread_stop+0x181/0x360\n hwrng_unregister+0x288/0x380\n virtrng_remove+0xe3/0x200\n\nThis patch fixes the race by protecting the global hwrng_fill pointer\ninside the rng_mutex lock, so that hwrng_fillfn() thread is stopped only\nonce, and calls to kthread_run() and kthread_stop() are serialized\nwith the lock held.\n\nTo avoid deadlock in hwrng_fillfn() while being stopped with the lock\nheld, we convert current_rng to RCU, so that get_current_rng() can read\ncurrent_rng without holding the lock. To remove the lock from put_rng(),\nwe also delay the actual cleanup into a work_struct.\n\nSince get_current_rng() no longer returns ERR_PTR values, the IS_ERR()\nchecks are removed from its callers.\n\nWith hwrng_fill protected by the rng_mutex lock, hwrng_fillfn() can no\nlonger clear hwrng_fill itself. Therefore, if hwrng_fillfn() returns\ndirectly after current_rng is dropped, kthread_stop() would be called on\na freed task_struct later. To fix this, hwrng_fillfn() calls schedule()\nnow to keep the task alive until being stopped. The kthread_stop() call\nis also moved from hwrng_unregister() to drop_current_rng(), ensuring\nkthread_stop() is called on all possible paths where current_rng becomes\nNULL, so that the thread would not wait forever."
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "drivers/char/hw_random/core.c",
                        "include/linux/hw_random.h"
                    ],
                    "versions": [
                        {
                            "version": "be4000bc4644d027c519b6361f5ae3bbfc52c347",
                            "lessThan": "d5b7730f06994499632026c30e38e0317c4569e2",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "be4000bc4644d027c519b6361f5ae3bbfc52c347",
                            "lessThan": "dcf416eb88eafe1e3c0f920a14bdffd10bc4d259",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "be4000bc4644d027c519b6361f5ae3bbfc52c347",
                            "lessThan": "ad38f2cdfef9a2f2899c30cad269baec5bfd4a5d",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "be4000bc4644d027c519b6361f5ae3bbfc52c347",
                            "lessThan": "cc2f39d6ac48e6e3cb2d6240bc0d6df839dd0828",
                            "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/char/hw_random/core.c",
                        "include/linux/hw_random.h"
                    ],
                    "versions": [
                        {
                            "version": "3.17",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "3.17",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.75",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.14",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.19.4",
                            "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": "3.17",
                                    "versionEndExcluding": "6.12.75"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "3.17",
                                    "versionEndExcluding": "6.18.14"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "3.17",
                                    "versionEndExcluding": "6.19.4"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "3.17",
                                    "versionEndExcluding": "7.0"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/d5b7730f06994499632026c30e38e0317c4569e2"
                },
                {
                    "url": "https://git.kernel.org/stable/c/dcf416eb88eafe1e3c0f920a14bdffd10bc4d259"
                },
                {
                    "url": "https://git.kernel.org/stable/c/ad38f2cdfef9a2f2899c30cad269baec5bfd4a5d"
                },
                {
                    "url": "https://git.kernel.org/stable/c/cc2f39d6ac48e6e3cb2d6240bc0d6df839dd0828"
                }
            ],
            "title": "hwrng: core - use RCU and work_struct to fix race condition",
            "x_generator": {
                "engine": "bippy-1.2.0"
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    }
}