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CVE-2026-46196

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: tracepoint: balance regfunc() on func_add() failure in tracepoint_add_func() When a tracepoint goes through the 0 -> 1 transition, tracepoint_add_func() invokes the subsystem's ext->regfunc() before attempting to install the new probe via func_add(). If func_add() then fails (for example, when allocate_probes() cannot allocate a new probe array under memory pressure and returns -ENOMEM), the function returns the error without calling the matching ext->unregfunc(), leaving the side effects of regfunc() behind with no installed probe to justify them. For syscall tracepoints this is particularly unpleasant: syscall_regfunc() bumps sys_tracepoint_refcount and sets SYSCALL_TRACEPOINT on every task. After a leaked failure, the refcount is stuck at a non-zero value with no consumer, and every task continues paying the syscall trace entry/exit overhead until reboot. Other subsystems providing regfunc()/unregfunc() pairs exhibit similarly scoped persistent state. Mirror the existing 1 -> 0 cleanup and call ext->unregfunc() in the func_add() error path, gated on the same condition used there so the unwind is symmetric with the registration.

Severity
MEDIUM
CVSS score
5.5 (v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-05-28 10:16:35.253000
Last modified
2026-11-06 17:17:44.243000
View original CVE JSON 
{
  "id": "CVE-2026-46196",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-05-28T10:16:35.253",
  "lastModified": "2026-11-06T17:17:44.243",
  "vulnStatus": "Modified",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracepoint: balance regfunc() on func_add() failure in tracepoint_add_func()\n\nWhen a tracepoint goes through the 0 -> 1 transition, tracepoint_add_func()\ninvokes the subsystem's ext->regfunc() before attempting to install the\nnew probe via func_add(). If func_add() then fails (for example, when\nallocate_probes() cannot allocate a new probe array under memory pressure\nand returns -ENOMEM), the function returns the error without calling the\nmatching ext->unregfunc(), leaving the side effects of regfunc() behind\nwith no installed probe to justify them.\n\nFor syscall tracepoints this is particularly unpleasant: syscall_regfunc()\nbumps sys_tracepoint_refcount and sets SYSCALL_TRACEPOINT on every task.\nAfter a leaked failure, the refcount is stuck at a non-zero value with no\nconsumer, and every task continues paying the syscall trace entry/exit\noverhead until reboot. Other subsystems providing regfunc()/unregfunc()\npairs exhibit similarly scoped persistent state.\n\nMirror the existing 1 -> 0 cleanup and call ext->unregfunc() in the\nfunc_add() error path, gated on the same condition used there so the\nunwind is symmetric with the registration."
    }
  ],
  "affected": [
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      "affectedData": [
        {
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          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
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          ],
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            },
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            },
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              "version": "5.15.210",
              "lessThanOrEqual": "5.15.*",
              "versionType": "semver",
              "status": "unaffected"
            },
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            },
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              "version": "7.1",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    },
    {
      "source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
      "affectedData": [
        {
          "vendor": "Siemens",
          "product": "SIMATIC S7-1500 TM MFP - GNU/Linux subsystem",
          "defaultStatus": "unknown",
          "versions": [
            {
              "version": "0",
              "lessThan": "*",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Primary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6
      }
    ],
    "ssvcV203": [
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        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-11-06T16:11:54.855002Z",
          "id": "CVE-2026-46196",
          "options": [
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              "exploitation": "none"
            },
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            }
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          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ]
    }
  ],
  "configurations": [
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          "negate": false,
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}