CVE-2026-72183

Estado: RecibidaAlta (8.4)—

In the Linux kernel, the following vulnerability has been resolved:

landlock: Fix LANDLOCK_SCOPE_SIGNAL bypass on the SIGIO path

LANDLOCK_SCOPE_SIGNAL must prevent a sandboxed process from signaling processes outside its Landlock domain. It can be bypassed through the asynchronous SIGIO delivery path.

A sandboxed process that owns any file or socket can arm it with fcntl(fd, F_SETOWN, -pgid), fcntl(fd, F_SETSIG, SIGKILL) and O_ASYNC, so that an I/O event makes the kernel deliver the chosen signal to the whole process group.

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As the head of its process group's task list (the default position right after fork()) that group can also hold the non-sandboxed process that launched it, e.g. a supervisor or a security monitor. The sandbox can thus kill or signal the processes LANDLOCK_SCOPE_SIGNAL is meant to protect from it.

The scope is enforced in hook_file_send_sigiotask() against the Landlock domain recorded at F_SETOWN time, not the live domain of the sender. control_current_fowner() decides whether to record that domain and skips recording it when the fowner target is in the caller's thread group, which is safe only for a single-task target (PIDTYPE_PID, PIDTYPE_TGID). For a process group (PIDTYPE_PGID) pid_task() returns only one member; recording is skipped whenever that member shares the caller's thread group, and hook_file_send_sigiotask() then lets the signal fan out to the whole group unchecked.

Record the domain for every non single-process target so the scope is enforced against each group member at delivery time.

That recording is necessary but not sufficient on its own: the kernel signals a process group through its members' thread-group leaders, and the leader of the registrant's own process can carry a different Landlock domain than the sibling thread that armed the owner. domain_is_scoped() would then deny that leader, even though commit 18eb75f3af40 ("landlock: Always allow signals between threads of the same process") requires same-process delivery to be allowed. hook_task_kill() avoids this by evaluating same_thread_group() live, per recipient; the SIGIO path instead delegates the whole decision to a single registration-time check, which a process-group fan-out cannot honor.

So also record the registrant's thread group next to its domain and exempt it at delivery: hook_file_send_sigiotask() allows the signal whenever the recipient belongs to the registrant's own process, restoring the same-process guarantee while keeping out-of-domain group members blocked. The direct kill() path (hook_task_kill) already evaluates the live domain and is unaffected.

[mic: Check pid_type earlier and improve comment, fix commit message, fix comment formatting]

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H
Puntuación base: 8.4

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.18%
Percentil entre todas las CVEs puntuadas: 7
Fecha de la puntuación: 6/10/2026

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation85 %
Impacto principalT1563 Remote Service Session Hijackinglateral movement75 %
Impacto secundarioT1529 System Shutdown/Rebootimpact70 %

Vulnerabilidad local (AV:L, PR:L) que permite escalada mediante bypass de LANDLOCK_SCOPE_SIGNAL para señalar procesos fuera del dominio sandbox. Impactos: control interactivo de sesión (señales de interacción) y negación de servicio (SIGKILL).

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

User Account Management Threat Intelligence Program Privileged Account Management Password Policies Network Segmentation Execution Prevention

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux Kernel^AI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-72183",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 8.4,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 5.8,
        "exploitabilityScore": 2
      }
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  "affected": [
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
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          "product": "Linux",
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            {
              "status": "affected",
              "version": "6.12.24",
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            {
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            {
              "status": "affected",
              "version": "6.14.3",
              "lessThan": "6.15",
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          "programFiles": [
            "security/landlock/fs.c",
            "security/landlock/fs.h",
            "security/landlock/task.c"
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          "defaultStatus": "unaffected"
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        {
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              "status": "affected",
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            },
            {
              "status": "unaffected",
              "version": "0",
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              "version": "6.18.40",
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            {
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              "version": "7.1.5",
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            {
              "status": "unaffected",
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              "versionType": "original_commit_for_fix",
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  "published": "2026-08-15T06:21:36.640",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/04916f7dc6d37cd478b06c86398c34a6963ac8c9",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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    {
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nlandlock: Fix LANDLOCK_SCOPE_SIGNAL bypass on the SIGIO path\n\nLANDLOCK_SCOPE_SIGNAL must prevent a sandboxed process from signaling\nprocesses outside its Landlock domain.  It can be bypassed through the\nasynchronous SIGIO delivery path.\n\nA sandboxed process that owns any file or socket can arm it with\nfcntl(fd, F_SETOWN, -pgid), fcntl(fd, F_SETSIG, SIGKILL) and O_ASYNC, so\nthat an I/O event makes the kernel deliver the chosen signal to the\nwhole process group.  As the head of its process group's task list (the\ndefault position right after fork()) that group can also hold the\nnon-sandboxed process that launched it, e.g. a supervisor or a security\nmonitor.  The sandbox can thus kill or signal the processes\nLANDLOCK_SCOPE_SIGNAL is meant to protect from it.\n\nThe scope is enforced in hook_file_send_sigiotask() against the Landlock\ndomain recorded at F_SETOWN time, not the live domain of the sender.\ncontrol_current_fowner() decides whether to record that domain and skips\nrecording it when the fowner target is in the caller's thread group,\nwhich is safe only for a single-task target (PIDTYPE_PID, PIDTYPE_TGID).\nFor a process group (PIDTYPE_PGID) pid_task() returns only one member;\nrecording is skipped whenever that member shares the caller's thread\ngroup, and hook_file_send_sigiotask() then lets the signal fan out to\nthe whole group unchecked.\n\nRecord the domain for every non single-process target so the scope is\nenforced against each group member at delivery time.\n\nThat recording is necessary but not sufficient on its own: the kernel\nsignals a process group through its members' thread-group leaders, and\nthe leader of the registrant's own process can carry a different\nLandlock domain than the sibling thread that armed the owner.\ndomain_is_scoped() would then deny that leader, even though commit\n18eb75f3af40 (\"landlock: Always allow signals between threads of the\nsame process\") requires same-process delivery to be allowed.\nhook_task_kill() avoids this by evaluating same_thread_group() live, per\nrecipient; the SIGIO path instead delegates the whole decision to a\nsingle registration-time check, which a process-group fan-out cannot\nhonor.\n\nSo also record the registrant's thread group next to its domain and\nexempt it at delivery: hook_file_send_sigiotask() allows the signal\nwhenever the recipient belongs to the registrant's own process,\nrestoring the same-process guarantee while keeping out-of-domain group\nmembers blocked.  The direct kill() path (hook_task_kill) already\nevaluates the live domain and is unaffected.\n\n[mic: Check pid_type earlier and improve comment, fix commit message,\nfix comment formatting]"
    }
  ],
  "lastModified": "2026-08-17T06:18:18.850",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}