CVE-2026-74605 (GCVE-0-2026-74605)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:31 – Updated: 2026-10-15 10:09
VLAI
Title
eventfs: Use children field for rcu head and add memory barriers
Summary
In the Linux kernel, the following vulnerability has been resolved: eventfs: Use children field for rcu head and add memory barriers When an eventfs inode is freed, it sets ei->is_freed and then uses its ei->list to add it to the srcu link list as the list field is a union with the rcu list head. As the ei->list is used to iterate over an SRCU protected list without taking the eventfs_mutex, there's nothing stopping the iteration over that list to see the ei->rcu instead of the ei->list and it will read a corrupt target. To fix this, change the union of the rcu list head with the children list. On freeing the eventfs inode, set the is_free and execute a smp_wmb() before adding the eventfs inode to the SRCU list. On iteration of the ei->children list, at the start, execute a smp_rmb() and then read the is_freed of the ei to see if the children list is still valid. If is_freed is set, then the ei_child read is not valid and the loop should exit immediately.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6666 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 704f960dbee2f1634f4b4e16f208cb16eaf41c1e , < 2b80707b9e27671e10840d17c6f8f774c4ad9847 (git)
Affected: 704f960dbee2f1634f4b4e16f208cb16eaf41c1e , < 004f7232e49730448f91665e76bdd7dff8e0c638 (git)
Affected: 704f960dbee2f1634f4b4e16f208cb16eaf41c1e , < f0ece16ffca7384787b692431961ce202907acf5 (git)
Affected: f3f41f444b321ec393edbc251e024fd62658ce55 (git)
Affected: 305c4e4d80aca2c2d9cf2ebdea56e2eca6d3a6aa (git)
Affected: 6.6.18 , < 6.7 (semver)
Affected: 6.7.6 , < 6.8 (semver)
guessed Create a notification for this product.
Linux Linux Affected: 6.8
Unaffected: 0 , < 6.8 (semver)
Unaffected: 6.18.57 , ≤ 6.18.* (semver)
Unaffected: 7.1.9 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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          "programFiles": [
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              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
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        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.57",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.9",
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              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\neventfs: Use children field for rcu head and add memory barriers\n\nWhen an eventfs inode is freed, it sets ei-\u003eis_freed and then uses its\nei-\u003elist to add it to the srcu link list as the list field is a union with\nthe rcu list head. As the ei-\u003elist is used to iterate over an SRCU\nprotected list without taking the eventfs_mutex, there\u0027s nothing stopping\nthe iteration over that list to see the ei-\u003ercu instead of the ei-\u003elist\nand it will read a corrupt target.\n\nTo fix this, change the union of the rcu list head with the children list.\nOn freeing the eventfs inode, set the is_free and execute a smp_wmb()\nbefore adding the eventfs inode to the SRCU list.\n\nOn iteration of the ei-\u003echildren list, at the start, execute a smp_rmb()\nand then read the is_freed of the ei to see if the children list is still\nvalid. If is_freed is set, then the ei_child read is not valid and the\nloop should exit immediately."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is reached only via local syscalls (getdents64/readdir on tracefs eventfs directories through eventfs_iterate); tracefs is a kernel pseudo-filesystem under /sys/kernel/tracing with no network, adjacent-wireless, or physical-device entry path.\nAC:L - A single multithreaded attacker can loop getdents on events/ or events/kprobes/ while concurrently adding/removing kprobes via kprobe_events writes that call eventfs_remove_dir; the attacker controls both the SRCU list walk and the free path, making the race reliably triggerable.\nPR:L - Exploitation needs only local tracefs read/write access (getdents plus kprobe_events to create/remove eventfs children); kprobe_events checks only LOCKDOWN_TRACEFS and DAC with no capable(), and tracing-group gid mounts, Android/ChromeOS, and developer systems commonly grant this to unprivileged users.\nUI:N - The attacker performs all concurrent directory reads and dynamic event removals in their own process; no separate victim mount, click, or configuration action is required beyond tracefs already being accessible on the system.\nS:U - The union misuse causes kernel heap/list corruption and use-after-free within the tracing filesystem subsystem on the same host; it does not cross VM, container, IOMMU, or other security boundaries to affect a different authority.\nC:H - During list_for_each_entry_srcu over ei-\u003echildren, a concurrently freed child repurposes ei-\u003elist (union with rcu_head) for SRCU teardown, so the iterator follows corrupt list pointers and dereferences freed or attacker-influenced kernel memory typical of UAF read primitives.\nI:H - Corrupt SRCU list traversal over freed eventfs_inode objects is classic kernel UAF memory corruption that can be combined with heap grooming from repeated kprobe create/delete to obtain arbitrary kernel writes and local privilege escalation, not merely a bounded crash.\nA:H - Following a child\u0027s list.next after the list/rcu union is switched during free_ei() readily causes invalid pointer dereferences, kernel oops, or panic; the race can be retriggered at will by alternating getdents with dynamic event teardown."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-15T10:09:20.401Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/2b80707b9e27671e10840d17c6f8f774c4ad9847"
        },
        {
          "url": "https://git.kernel.org/stable/c/004f7232e49730448f91665e76bdd7dff8e0c638"
        },
        {
          "url": "https://git.kernel.org/stable/c/f0ece16ffca7384787b692431961ce202907acf5"
        }
      ],
      "title": "eventfs: Use children field for rcu head and add memory barriers",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74605",
    "datePublished": "2026-08-22T15:31:53.063Z",
    "dateReserved": "2026-08-15T05:44:03.919Z",
    "dateUpdated": "2026-10-15T10:09:20.401Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
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      "date": "2026-10-16",
      "epss": "0.00173",
      "percentile": "0.06319"
    },
    "microsoft_vex": {
      "current_release_date": "2026-09-24T02:39:27.000Z",
      "cve": "CVE-2026-74605",
      "id": "msrc_CVE-2026-74605",
      "initial_release_date": "2026-08-24T01:03:04.000Z",
      "product_status:known_affected": "3",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "eventfs: Use children field for rcu head and add memory barriers",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74605.json",
      "version": "5"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "fs/tracefs/event_inode.c",
                  "fs/tracefs/internal.h"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
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                    "versionType": "git"
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                  {
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                    "versionType": "git"
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                    "status": "affected",
                    "version": "305c4e4d80aca2c2d9cf2ebdea56e2eca6d3a6aa",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "6.7",
                    "status": "affected",
                    "version": "6.6.18",
                    "versionType": "semver"
                  },
                  {
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                    "status": "affected",
                    "version": "6.7.6",
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              },
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                "product": "Linux",
                "programFiles": [
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                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
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                    "status": "unaffected",
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                    "status": "unaffected",
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                  {
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                    "status": "unaffected",
                    "version": "7.1.9",
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                    "version": "7.2",
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\neventfs: Use children field for rcu head and add memory barriers\n\nWhen an eventfs inode is freed, it sets ei-\u003eis_freed and then uses its\nei-\u003elist to add it to the srcu link list as the list field is a union with\nthe rcu list head. As the ei-\u003elist is used to iterate over an SRCU\nprotected list without taking the eventfs_mutex, there\u0027s nothing stopping\nthe iteration over that list to see the ei-\u003ercu instead of the ei-\u003elist\nand it will read a corrupt target.\n\nTo fix this, change the union of the rcu list head with the children list.\nOn freeing the eventfs inode, set the is_free and execute a smp_wmb()\nbefore adding the eventfs inode to the SRCU list.\n\nOn iteration of the ei-\u003echildren list, at the start, execute a smp_rmb()\nand then read the is_freed of the ei to see if the children list is still\nvalid. If is_freed is set, then the ei_child read is not valid and the\nloop should exit immediately."
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\neventfs: Usar el campo children para la cabecera rcu y a\u00f1adir barreras de memoria\n\nCuando un inodo eventfs es liberado, establece ei -\u003e is_freed y luego usa su ei -\u003e list para a\u00f1adirlo a la lista de enlaces srcu ya que el campo list es una uni\u00f3n con la cabecera de la lista rcu. Como el ei -\u003e list se usa para iterar sobre una lista protegida por SRCU sin tomar el eventfs_mutex, no hay nada que impida que la iteraci\u00f3n sobre esa lista vea el ei -\u003e rcu en lugar del ei -\u003e list y leer\u00e1 un objetivo corrupto.\n\nPara solucionar esto, cambiar la uni\u00f3n de la cabecera de la lista rcu con la lista children. Al liberar el inodo eventfs, establecer el is_free y ejecutar un smp_wmb() antes de a\u00f1adir el inodo eventfs a la lista SRCU.\n\nEn la iteraci\u00f3n de la lista ei -\u003e children, al inicio, ejecutar un smp_rmb() y luego leer el is_freed del ei para ver si la lista children sigue siendo v\u00e1lida. Si is_freed est\u00e1 establecido, entonces la lectura de ei_child no es v\u00e1lida y el bucle deber\u00eda salir inmediatamente."
          }
        ],
        "id": "CVE-2026-74605",
        "lastModified": "2026-10-15T11:17:48.277",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
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              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
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        "published": "2026-08-22T16:16:32.977",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/004f7232e49730448f91665e76bdd7dff8e0c638"
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          },
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-25T08:50:30+00:00",
      "cve": "CVE-2026-74605",
      "id": "CVE-2026-74605",
      "initial_release_date": "2026-08-22T00:00:00+00:00",
      "product_status:known_affected": "76",
      "product_status:known_not_affected": "198",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: eventfs: Use children field for rcu head and add memory barriers",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74605.json",
      "version": "3"
    }
  }
}



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