{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2025-21899",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2024-12-29T08:45:45.783Z",
        "datePublished": "2025-04-01T15:26:50.791Z",
        "dateUpdated": "2026-08-05T11:55:14.373Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-08-05T11:55:14.373Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix bad hist from corrupting named_triggers list\n\nThe following commands causes a crash:\n\n ~# cd /sys/kernel/tracing/events/rcu/rcu_callback\n ~# echo 'hist:name=bad:keys=common_pid:onmax(bogus).save(common_pid)' > trigger\n bash: echo: write error: Invalid argument\n ~# echo 'hist:name=bad:keys=common_pid' > trigger\n\nBecause the following occurs:\n\nevent_trigger_write() {\n  trigger_process_regex() {\n    event_hist_trigger_parse() {\n\n      data = event_trigger_alloc(..);\n\n      event_trigger_register(.., data) {\n        cmd_ops->reg(.., data, ..) [hist_register_trigger()] {\n          data->ops->init() [event_hist_trigger_init()] {\n            save_named_trigger(name, data) {\n              list_add(&data->named_list, &named_triggers);\n            }\n          }\n        }\n      }\n\n      ret = create_actions(); (return -EINVAL)\n      if (ret)\n        goto out_unreg;\n[..]\n      ret = hist_trigger_enable(data, ...) {\n        list_add_tail_rcu(&data->list, &file->triggers); <<<---- SKIPPED!!! (this is important!)\n[..]\n out_unreg:\n      event_hist_unregister(.., data) {\n        cmd_ops->unreg(.., data, ..) [hist_unregister_trigger()] {\n          list_for_each_entry(iter, &file->triggers, list) {\n            if (!hist_trigger_match(data, iter, named_data, false))   <- never matches\n                continue;\n            [..]\n            test = iter;\n          }\n          if (test && test->ops->free) <<<-- test is NULL\n\n            test->ops->free(test) [event_hist_trigger_free()] {\n              [..]\n              if (data->name)\n                del_named_trigger(data) {\n                  list_del(&data->named_list);  <<<<-- NEVER gets removed!\n                }\n              }\n           }\n         }\n\n         [..]\n         kfree(data); <<<-- frees item but it is still on list\n\nThe next time a hist with name is registered, it causes an u-a-f bug and\nthe kernel can crash.\n\nMove the code around such that if event_trigger_register() succeeds, the\nnext thing called is hist_trigger_enable() which adds it to the list.\n\nA bunch of actions is called if get_named_trigger_data() returns false.\nBut that doesn't need to be called after event_trigger_register(), so it\ncan be moved up, allowing event_trigger_register() to be called just\nbefore hist_trigger_enable() keeping them together and allowing the\nfile->triggers to be properly populated."
                }
            ],
            "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 vulnerability is reached only by writing a hist trigger command to a tracefs file (`/sys/kernel/tracing/events/*/trigger`) via the write(2) syscall. There is no network or remote data path into `event_hist_trigger_parse()`.\nAC:L - Triggering is fully deterministic — one failing `hist:name=bad:...onmax(bogus)...` write leaves the freed object linked in the global `named_triggers` list, and a second `hist:name=bad` write dereferences it; no race and no uncontrollable preconditions. `CONFIG_HIST_TRIGGERS=y` is standard in mainstream distro and Android kernels, and slab reclaim of the freed `event_trigger_data` is attacker-influenced via ordinary heap spraying.\nPR:L - No capability check exists on the code path; access is gated purely by tracefs file permissions, and tracefs is routinely delegated to a non-root tracing/shell group (Android shell, ChromeOS debugd, perf/tracing groups) via the `gid=` mount option. A local unprivileged user with that ordinary tracing access can execute the full sequence.\nUI:N - The attacker performs both writes themselves; no victim action or cooperation is needed at any point.\nS:U - The use-after-free and list corruption occur in kernel memory within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - `find_named_trigger()` and `hist_trigger_match()` dereference the freed object's `name` and `private_data` pointers, so after reclaiming the slab object the attacker controls those pointers and obtains an arbitrary kernel-memory read primitive, plus leakage of the `named_triggers` list-head address.\nI:H - The freed object remains on a global list, so subsequent `list_add`/`list_del` operations write through attacker-controlled `named_list` pointers, and `data->private_data = named_data->private_data` produces type confusion into `hist_trigger_data` — a classic UAF write primitive usable for control-flow hijack.\nA:H - As stated in the commit, the second named-hist registration causes a use-after-free that crashes the kernel; list corruption reliably produces an oops or panic, denying service to the whole system."
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "kernel/trace/trace_events_hist.c"
                    ],
                    "versions": [
                        {
                            "version": "067fe038e70f6e64960d26a79c4df5f1413d0f13",
                            "lessThan": "5ae1b18f05ee2b849dc03b6c15d7da0c1c6efa77",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "067fe038e70f6e64960d26a79c4df5f1413d0f13",
                            "lessThan": "43b254d46c740bf9dbe65709afa021dd726dfa99",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "067fe038e70f6e64960d26a79c4df5f1413d0f13",
                            "lessThan": "435d2964af815aae456db554c62963b4515f19d0",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "067fe038e70f6e64960d26a79c4df5f1413d0f13",
                            "lessThan": "f1ae50cfb818ce1ac7a674406dfadb7653e2552d",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "067fe038e70f6e64960d26a79c4df5f1413d0f13",
                            "lessThan": "6f86bdeab633a56d5c6dccf1a2c5989b6a5e323e",
                            "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_events_hist.c"
                    ],
                    "versions": [
                        {
                            "version": "4.17",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "4.17",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.1.130",
                            "lessThanOrEqual": "6.1.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.6.81",
                            "lessThanOrEqual": "6.6.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.18",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.13.6",
                            "lessThanOrEqual": "6.13.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.14",
                            "lessThanOrEqual": "*",
                            "status": "unaffected",
                            "versionType": "original_commit_for_fix"
                        }
                    ]
                }
            ],
            "cpeApplicability": [
                {
                    "nodes": [
                        {
                            "operator": "OR",
                            "negate": false,
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                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                                    "versionEndExcluding": "6.1.130"
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                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/5ae1b18f05ee2b849dc03b6c15d7da0c1c6efa77"
                },
                {
                    "url": "https://git.kernel.org/stable/c/43b254d46c740bf9dbe65709afa021dd726dfa99"
                },
                {
                    "url": "https://git.kernel.org/stable/c/435d2964af815aae456db554c62963b4515f19d0"
                },
                {
                    "url": "https://git.kernel.org/stable/c/f1ae50cfb818ce1ac7a674406dfadb7653e2552d"
                },
                {
                    "url": "https://git.kernel.org/stable/c/6f86bdeab633a56d5c6dccf1a2c5989b6a5e323e"
                }
            ],
            "title": "tracing: Fix bad hist from corrupting named_triggers list",
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        "adp": [
            {
                "title": "CVE Program Container",
                "references": [
                    {
                        "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html"
                    }
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                "providerMetadata": {
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                    "shortName": "CVE",
                    "dateUpdated": "2025-11-03T19:38:45.924Z"
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