CVE-2025-39813 (GCVE-0-2025-39813)

Vulnerability from cvelistv5 – Published: 2025-09-16 13:00 – Updated: 2026-05-12 12:07
VLAI
Title
ftrace: Fix potential warning in trace_printk_seq during ftrace_dump
Summary
In the Linux kernel, the following vulnerability has been resolved: ftrace: Fix potential warning in trace_printk_seq during ftrace_dump When calling ftrace_dump_one() concurrently with reading trace_pipe, a WARN_ON_ONCE() in trace_printk_seq() can be triggered due to a race condition. The issue occurs because: CPU0 (ftrace_dump) CPU1 (reader) echo z > /proc/sysrq-trigger !trace_empty(&iter) trace_iterator_reset(&iter) <- len = size = 0 cat /sys/kernel/tracing/trace_pipe trace_find_next_entry_inc(&iter) __find_next_entry ring_buffer_empty_cpu <- all empty return NULL trace_printk_seq(&iter.seq) WARN_ON_ONCE(s->seq.len >= s->seq.size) In the context between trace_empty() and trace_find_next_entry_inc() during ftrace_dump, the ring buffer data was consumed by other readers. This caused trace_find_next_entry_inc to return NULL, failing to populate `iter.seq`. At this point, due to the prior trace_iterator_reset, both `iter.seq.len` and `iter.seq.size` were set to 0. Since they are equal, the WARN_ON_ONCE condition is triggered. Move the trace_printk_seq() into the if block that checks to make sure the return value of trace_find_next_entry_inc() is non-NULL in ftrace_dump_one(), ensuring the 'iter.seq' is properly populated before subsequent operations.
Severity
4.7 (Medium)
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 7061 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: d769041f865330034131525ee6a7f72eb4af2a24 , < f299353e7ccbcc5c2ed8993c48fbe7609cbe729a (git)
Affected: d769041f865330034131525ee6a7f72eb4af2a24 , < 5ab0ec206deb99eb3baf8f1d7602aeaa91dbcc85 (git)
Affected: d769041f865330034131525ee6a7f72eb4af2a24 , < a6f0f8873cc30fd4543b09adf03f7f51d293f0e6 (git)
Affected: d769041f865330034131525ee6a7f72eb4af2a24 , < e80ff23ba8bdb0f41a1afe2657078e4097d13a9a (git)
Affected: d769041f865330034131525ee6a7f72eb4af2a24 , < 28c8fb7ae2ad27d81c8de3c4fe608c509f6a18aa (git)
Affected: d769041f865330034131525ee6a7f72eb4af2a24 , < ced94e137e6cd5e79c65564841d3b7695d0f5fa3 (git)
Affected: d769041f865330034131525ee6a7f72eb4af2a24 , < fbd4cf7ee4db65ef36796769fe978e9eba6f0de4 (git)
Affected: d769041f865330034131525ee6a7f72eb4af2a24 , < 4013aef2ced9b756a410f50d12df9ebe6a883e4a (git)
guessed Create a notification for this product.
Linux Linux Affected: 2.6.28
Unaffected: 0 , < 2.6.28 (semver)
Unaffected: 5.4.298 , ≤ 5.4.* (semver)
Unaffected: 5.10.242 , ≤ 5.10.* (semver)
Unaffected: 5.15.191 , ≤ 5.15.* (semver)
Unaffected: 6.1.150 , ≤ 6.1.* (semver)
Unaffected: 6.6.104 , ≤ 6.6.* (semver)
Unaffected: 6.12.45 , ≤ 6.12.* (semver)
Unaffected: 6.16.5 , ≤ 6.16.* (semver)
Unaffected: 6.17 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Siemens SIMATIC CN 4100 Affected: 0 , < V5.0 (custom)
guessed Create a notification for this product.
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                    "matchCriteriaId": "327D22EF-390B-454C-BD31-2ED23C998A1C",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:*",
                    "matchCriteriaId": "C730CD9A-D969-4A8E-9522-162AAF7C0EE9",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          },
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*",
                    "matchCriteriaId": "FA6FEEC2-9F11-4643-8827-749718254FED",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nftrace: Fix potential warning in trace_printk_seq during ftrace_dump\n\nWhen calling ftrace_dump_one() concurrently with reading trace_pipe,\na WARN_ON_ONCE() in trace_printk_seq() can be triggered due to a race\ncondition.\n\nThe issue occurs because:\n\nCPU0 (ftrace_dump)                              CPU1 (reader)\necho z \u003e /proc/sysrq-trigger\n\n!trace_empty(\u0026iter)\ntrace_iterator_reset(\u0026iter) \u003c- len = size = 0\n                                                cat /sys/kernel/tracing/trace_pipe\ntrace_find_next_entry_inc(\u0026iter)\n  __find_next_entry\n    ring_buffer_empty_cpu \u003c- all empty\n  return NULL\n\ntrace_printk_seq(\u0026iter.seq)\n  WARN_ON_ONCE(s-\u003eseq.len \u003e= s-\u003eseq.size)\n\nIn the context between trace_empty() and trace_find_next_entry_inc()\nduring ftrace_dump, the ring buffer data was consumed by other readers.\nThis caused trace_find_next_entry_inc to return NULL, failing to populate\n`iter.seq`. At this point, due to the prior trace_iterator_reset, both\n`iter.seq.len` and `iter.seq.size` were set to 0. Since they are equal,\nthe WARN_ON_ONCE condition is triggered.\n\nMove the trace_printk_seq() into the if block that checks to make sure the\nreturn value of trace_find_next_entry_inc() is non-NULL in\nftrace_dump_one(), ensuring the \u0027iter.seq\u0027 is properly populated before\nsubsequent operations."
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nftrace: Soluciona una advertencia potencial en trace_printk_seq durante ftrace_dump\n\nAl llamar a ftrace_dump_one() concurrentemente con la lectura de trace_pipe, una WARN_ON_ONCE() en trace_printk_seq() puede ser activada debido a una condici\u00f3n de carrera.\n\nEl problema ocurre porque:\n\nCPU0 (ftrace_dump)                              CPU1 (lector)\necho z \u003e /proc/sysrq-trigger\n\n!trace_empty(\u0026iter)\ntrace_iterator_reset(\u0026iter) \u003c- len = size = 0\n                                                cat /sys/kernel/tracing/trace_pipe\ntrace_find_next_entry_inc(\u0026iter)\n  __find_next_entry\n    ring_buffer_empty_cpu \u003c- todo vac\u00edo\n  return NULL\n\ntrace_printk_seq(\u0026iter.seq)\n  WARN_ON_ONCE(s-\u003eseq.len \u003e= s-\u003eseq.size)\n\nEn el contexto entre trace_empty() y trace_find_next_entry_inc() durante ftrace_dump, los datos del b\u00fafer circular fueron consumidos por otros lectores. Esto hizo que trace_find_next_entry_inc devolviera NULL, fallando en poblar \u0027iter.seq\u0027. En este punto, debido al trace_iterator_reset previo, tanto \u0027iter.seq.len\u0027 como \u0027iter.seq.size\u0027 se establecieron en 0. Dado que son iguales, la condici\u00f3n WARN_ON_ONCE se activa.\n\nMover trace_printk_seq() al bloque \u0027if\u0027 que verifica que el valor de retorno de trace_find_next_entry_inc() no sea NULL en ftrace_dump_one(), asegurando que \u0027iter.seq\u0027 se pueble correctamente antes de operaciones posteriores."
          }
        ],
        "id": "CVE-2025-39813",
        "lastModified": "2026-10-19T21:10:00.160",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "HIGH",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 4.7,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.0,
              "impactScore": 3.6,
              "source": "nvd@nist.gov",
              "type": "Primary"
            }
          ]
        },
        "published": "2025-09-16T13:15:55.150",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/28c8fb7ae2ad27d81c8de3c4fe608c509f6a18aa"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/4013aef2ced9b756a410f50d12df9ebe6a883e4a"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/5ab0ec206deb99eb3baf8f1d7602aeaa91dbcc85"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/a6f0f8873cc30fd4543b09adf03f7f51d293f0e6"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/ced94e137e6cd5e79c65564841d3b7695d0f5fa3"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/e80ff23ba8bdb0f41a1afe2657078e4097d13a9a"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/f299353e7ccbcc5c2ed8993c48fbe7609cbe729a"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/fbd4cf7ee4db65ef36796769fe978e9eba6f0de4"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Third Party Advisory"
            ],
            "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Third Party Advisory"
            ],
            "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"
          },
          {
            "source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
            "url": "https://cert-portal.siemens.com/productcert/html/ssa-032379.html"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Modified",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-362"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-06-30T10:22:13+00:00",
      "cve": "CVE-2025-39813",
      "id": "CVE-2025-39813",
      "initial_release_date": "2025-09-16T00:00:00+00:00",
      "product_status:known_affected": "260",
      "product_status:known_not_affected": "14",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Linux kernel: Denial of Service in ftrace due to race condition in trace_printk_seq",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-39813.json",
      "version": "3"
    }
  }
}



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