CVE-2026-45957

Estado: AnalizadaAlta (7.1)—

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

rcu: Fix rcu_read_unlock() deadloop due to softirq

Commit 5f5fa7ea89dc ("rcu: Don't use negative nesting depth in __rcu_read_unlock()") removes the recursion-protection code from __rcu_read_unlock(). Therefore, we could invoke the deadloop in raise_softirq_irqoff() with ftrace enabled as follows:

Commit b41642c87716 ("rcu: Fix rcu_read_unlock() deadloop due to IRQ work") fixed the infinite loop in rcu_read_unlock_special() for IRQ work by setting a flag before calling irq_work_queue_on(). We fix this issue by setting the same flag before calling raise_softirq_irqoff() and rename the flag to defer_qs_pending for more common.

Detalles técnicos trazas, registros y código del informe original

WARNING: CPU: 0 PID: 0 at kernel/trace/trace.c:3021 __ftrace_trace_stack.constprop.0+0x172/0x180
Modules linked in: my_irq_work(O)
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G O 6.18.0-rc7-dirty #23 PREEMPT(full)
Tainted: [O]=OOT_MODULE
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
RIP: 0010:__ftrace_trace_stack.constprop.0+0x172/0x180
RSP: 0018:ffffc900000034a8 EFLAGS: 00010002
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000000000
RDX: 0000000000000003 RSI: ffffffff826d7b87 RDI: ffffffff826e9329
RBP: 0000000000090009 R08: 0000000000000005 R09: ffffffff82afbc4c
R10: 0000000000000008 R11: 0000000000011d7a R12: 0000000000000000
R13: ffff888003874100 R14: 0000000000000003 R15: ffff8880038c1054
FS:  0000000000000000(0000) GS:ffff8880fa8ea000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055b31fa7f540 CR3: 00000000078f4005 CR4: 0000000000770ef0
PKRU: 55555554
Call Trace:
 <IRQ>
 trace_buffer_unlock_commit_regs+0x6d/0x220
 trace_event_buffer_commit+0x5c/0x260
 trace_event_raw_event_softirq+0x47/0x80
 raise_softirq_irqoff+0x6e/0xa0
 rcu_read_unlock_special+0xb1/0x160
 unwind_next_frame+0x203/0x9b0
 __unwind_start+0x15d/0x1c0
 arch_stack_walk+0x62/0xf0
 stack_trace_save+0x48/0x70
 __ftrace_trace_stack.constprop.0+0x144/0x180
 trace_buffer_unlock_commit_regs+0x6d/0x220
 trace_event_buffer_commit+0x5c/0x260
 trace_event_raw_event_softirq+0x47/0x80
 raise_softirq_irqoff+0x6e/0xa0
 rcu_read_unlock_special+0xb1/0x160
 unwind_next_frame+0x203/0x9b0
 __unwind_start+0x15d/0x1c0
 arch_stack_walk+0x62/0xf0
 stack_trace_save+0x48/0x70
 __ftrace_trace_stack.constprop.0+0x144/0x180
 trace_buffer_unlock_commit_regs+0x6d/0x220
 trace_event_buffer_commit+0x5c/0x260
 trace_event_raw_event_softirq+0x47/0x80
 raise_softirq_irqoff+0x6e/0xa0
 rcu_read_unlock_special+0xb1/0x160
 unwind_next_frame+0x203/0x9b0
 __unwind_start+0x15d/0x1c0
 arch_stack_walk+0x62/0xf0
 stack_trace_save+0x48/0x70
 __ftrace_trace_stack.constprop.0+0x144/0x180
 trace_buffer_unlock_commit_regs+0x6d/0x220
 trace_event_buffer_commit+0x5c/0x260
 trace_event_raw_event_softirq+0x47/0x80
 raise_softirq_irqoff+0x6e/0xa0
 rcu_read_unlock_special+0xb1/0x160
 __is_insn_slot_addr+0x54/0x70
 kernel_text_address+0x48/0xc0
 __kernel_text_address+0xd/0x40
 unwind_get_return_address+0x1e/0x40
 arch_stack_walk+0x9c/0xf0
 stack_trace_save+0x48/0x70
 __ftrace_trace_stack.constprop.0+0x144/0x180
 trace_buffer_unlock_commit_regs+0x6d/0x220
 trace_event_buffer_commit+0x5c/0x260
 trace_event_raw_event_softirq+0x47/0x80
 __raise_softirq_irqoff+0x61/0x80
 __flush_smp_call_function_queue+0x115/0x420
 __sysvec_call_function_single+0x17/0xb0
 sysvec_call_function_single+0x8c/0xc0
 </IRQ>

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Puntuación base: 7.1

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.17%
Percentil entre todas las CVEs puntuadas: 5
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 escalation75 %
Impacto principalT1499.004 Application or System Exploitationimpact70 %

Vulnerabilidad local de kernel (AV:L, PR:L) que causa deadloop/DoS al invocar raise_softirq_irqoff() con ftrace habilitado, impactando disponibilidad del sistema (A:H).

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

Threat Intelligence Program Filter Network Traffic Execution Prevention Application Isolation and Sandboxing Exploit Protection Update Software

Tecnologías afectadas (1)

Linux — Linux Kernel

CWE

CWE-125

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2026-45957",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.1,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.2,
        "exploitabilityScore": 1.8
      }
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            "kernel/rcu/tree_plugin.h"
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              "version": "0",
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              "versionType": "semver"
            },
            {
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              "version": "6.6.128",
              "versionType": "semver",
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              "version": "6.12.75",
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              "version": "6.18.14",
              "versionType": "semver",
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            "kernel/rcu/tree_plugin.h"
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  "published": "2026-05-27T14:17:12.280",
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "tags": [
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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      "tags": [
        "Patch"
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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  "vulnStatus": "Analyzed",
  "weaknesses": [
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      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-125"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrcu: Fix rcu_read_unlock() deadloop due to softirq\n\nCommit 5f5fa7ea89dc (\"rcu: Don't use negative nesting depth in\n__rcu_read_unlock()\") removes the recursion-protection code from\n__rcu_read_unlock(). Therefore, we could invoke the deadloop in\nraise_softirq_irqoff() with ftrace enabled as follows:\n\nWARNING: CPU: 0 PID: 0 at kernel/trace/trace.c:3021 __ftrace_trace_stack.constprop.0+0x172/0x180\nModules linked in: my_irq_work(O)\nCPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G O 6.18.0-rc7-dirty #23 PREEMPT(full)\nTainted: [O]=OOT_MODULE\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014\nRIP: 0010:__ftrace_trace_stack.constprop.0+0x172/0x180\nRSP: 0018:ffffc900000034a8 EFLAGS: 00010002\nRAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000000000\nRDX: 0000000000000003 RSI: ffffffff826d7b87 RDI: ffffffff826e9329\nRBP: 0000000000090009 R08: 0000000000000005 R09: ffffffff82afbc4c\nR10: 0000000000000008 R11: 0000000000011d7a R12: 0000000000000000\nR13: ffff888003874100 R14: 0000000000000003 R15: ffff8880038c1054\nFS:  0000000000000000(0000) GS:ffff8880fa8ea000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 000055b31fa7f540 CR3: 00000000078f4005 CR4: 0000000000770ef0\nPKRU: 55555554\nCall Trace:\n <IRQ>\n trace_buffer_unlock_commit_regs+0x6d/0x220\n trace_event_buffer_commit+0x5c/0x260\n trace_event_raw_event_softirq+0x47/0x80\n raise_softirq_irqoff+0x6e/0xa0\n rcu_read_unlock_special+0xb1/0x160\n unwind_next_frame+0x203/0x9b0\n __unwind_start+0x15d/0x1c0\n arch_stack_walk+0x62/0xf0\n stack_trace_save+0x48/0x70\n __ftrace_trace_stack.constprop.0+0x144/0x180\n trace_buffer_unlock_commit_regs+0x6d/0x220\n trace_event_buffer_commit+0x5c/0x260\n trace_event_raw_event_softirq+0x47/0x80\n raise_softirq_irqoff+0x6e/0xa0\n rcu_read_unlock_special+0xb1/0x160\n unwind_next_frame+0x203/0x9b0\n __unwind_start+0x15d/0x1c0\n arch_stack_walk+0x62/0xf0\n stack_trace_save+0x48/0x70\n __ftrace_trace_stack.constprop.0+0x144/0x180\n trace_buffer_unlock_commit_regs+0x6d/0x220\n trace_event_buffer_commit+0x5c/0x260\n trace_event_raw_event_softirq+0x47/0x80\n raise_softirq_irqoff+0x6e/0xa0\n rcu_read_unlock_special+0xb1/0x160\n unwind_next_frame+0x203/0x9b0\n __unwind_start+0x15d/0x1c0\n arch_stack_walk+0x62/0xf0\n stack_trace_save+0x48/0x70\n __ftrace_trace_stack.constprop.0+0x144/0x180\n trace_buffer_unlock_commit_regs+0x6d/0x220\n trace_event_buffer_commit+0x5c/0x260\n trace_event_raw_event_softirq+0x47/0x80\n raise_softirq_irqoff+0x6e/0xa0\n rcu_read_unlock_special+0xb1/0x160\n __is_insn_slot_addr+0x54/0x70\n kernel_text_address+0x48/0xc0\n __kernel_text_address+0xd/0x40\n unwind_get_return_address+0x1e/0x40\n arch_stack_walk+0x9c/0xf0\n stack_trace_save+0x48/0x70\n __ftrace_trace_stack.constprop.0+0x144/0x180\n trace_buffer_unlock_commit_regs+0x6d/0x220\n trace_event_buffer_commit+0x5c/0x260\n trace_event_raw_event_softirq+0x47/0x80\n __raise_softirq_irqoff+0x61/0x80\n __flush_smp_call_function_queue+0x115/0x420\n __sysvec_call_function_single+0x17/0xb0\n sysvec_call_function_single+0x8c/0xc0\n </IRQ>\n\nCommit b41642c87716 (\"rcu: Fix rcu_read_unlock() deadloop due to IRQ work\")\nfixed the infinite loop in rcu_read_unlock_special() for IRQ work by\nsetting a flag before calling irq_work_queue_on(). We fix this issue by\nsetting the same flag before calling raise_softirq_irqoff() and rename the\nflag to defer_qs_pending for more common."
    }
  ],
  "lastModified": "2026-06-17T10:52:47.687",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
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          "operator": "OR"
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  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}