CVE-2026-80671 (GCVE-0-2026-80671)

Vulnerability from cvelistv5 – Published: 2026-08-28 06:49 – Updated: 2026-08-29 06:21
VLAI
Title
perf sched: Fix register_pid() overflow, strcpy, and BUG_ON
Summary
In the Linux kernel, the following vulnerability has been resolved: perf sched: Fix register_pid() overflow, strcpy, and BUG_ON register_pid() has several issues when processing untrusted perf.data: 1. Integer overflow: (pid + 1) * sizeof(struct task_desc *) can wrap to a small value on 32-bit systems when pid is large (e.g. 0x40000000), causing realloc to return a tiny buffer followed by out-of-bounds writes in the initialization loop. 2. Heap buffer overflow: strcpy(task->comm, comm) copies the untrusted comm string into a fixed 20-byte COMM_LEN buffer with no length check. 3. BUG_ON on allocation failure: perf.data is untrusted input, so allocation failures should be handled gracefully rather than killing the process. 4. Realloc of sched->tasks assigned directly back, leaking the old pointer on failure; nr_tasks incremented before the realloc, leaving corrupted state on failure. Cap pid at PID_MAX_LIMIT (4194304, matching the kernel's maximum on 64-bit), replace strcpy with strlcpy, guard against NULL comm, replace BUG_ON with NULL returns using safe realloc patterns, and add NULL checks in callers that dereference the result.
Severity
9.3 (Critical)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: ec156764d424dd67283c2cd5e9f6f1b8388364ac , < 652cea73b7b7b7c622a2be670e44e3c499c6d49f (git)
Affected: ec156764d424dd67283c2cd5e9f6f1b8388364ac , < 5ea1dcc9418c4e06ce29ed5170596f497ba86872 (git)
Affected: ec156764d424dd67283c2cd5e9f6f1b8388364ac , < 5949d339f5ec98752d56dcd4e36f619a59d513a5 (git)
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Linux Linux Affected: 2.6.32
Unaffected: 0 , < 2.6.32 (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "tools/perf/builtin-sched.c"
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          "vendor": "Linux",
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      "cpeApplicability": [
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          "nodes": [
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nperf sched: Fix register_pid() overflow, strcpy, and BUG_ON\n\nregister_pid() has several issues when processing untrusted perf.data:\n\n1. Integer overflow: (pid + 1) * sizeof(struct task_desc *) can wrap\n   to a small value on 32-bit systems when pid is large (e.g.\n   0x40000000), causing realloc to return a tiny buffer followed by\n   out-of-bounds writes in the initialization loop.\n\n2. Heap buffer overflow: strcpy(task-\u003ecomm, comm) copies the\n   untrusted comm string into a fixed 20-byte COMM_LEN buffer with\n   no length check.\n\n3. BUG_ON on allocation failure: perf.data is untrusted input, so\n   allocation failures should be handled gracefully rather than\n   killing the process.\n\n4. Realloc of sched-\u003etasks assigned directly back, leaking the old\n   pointer on failure; nr_tasks incremented before the realloc,\n   leaving corrupted state on failure.\n\nCap pid at PID_MAX_LIMIT (4194304, matching the kernel\u0027s maximum\non 64-bit), replace strcpy with strlcpy, guard against NULL comm,\nreplace BUG_ON with NULL returns using safe realloc patterns, and\nadd NULL checks in callers that dereference the result."
        }
      ],
      "metrics": [
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          "cvssV3_1": {
            "baseScore": 9.3,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The flaw is in userspace perf\u0027s builtin-sched.c reached only when a local user runs perf sched replay or perf sched latency against a crafted perf.data file via perf_session__process_events; it is not triggered by remote network packets, kernel syscalls, or in-kernel sched code.\nAC:L - The attacker fully controls untrusted perf.data sched_switch/sched_wakeup fields (prev_pid, next_pid, prev_comm, next_comm); large PIDs and overlong comm strings deterministically hit the integer-overflow realloc path or strcpy heap overflow without races or victim-specific memory layout.\nPR:N - In the malicious-trace threat model an external party needs no account or privileges on the victim host\u2014they only supply a crafted perf.data file for a developer, support engineer, or CI job to analyze with perf sched replay/latency.\nUI:N - Once a trace is submitted to triage or CI, perf sched replay/latency parses perf.data non-interactively through perf_sched__read_events without further per-event operator actions beyond automated invocation of the perf command on the supplied file.\nS:C - Malicious sched metadata embedded in an externally supplied perf.data crosses from the untrusted reporter/artifact domain into the analyst or CI host security authority when perf parses that file, matching the kernel CNA untrusted-artifact model used for crafted filesystem images.\nC:H - Integer-overflow-driven out-of-bounds writes into the pid_to_task table and strcpy heap overflow past task_desc.comm[20] corrupt adjacent heap objects and can disclose process memory beyond a few bounded bytes.\nI:H - Attacker-controlled overflows corrupt task_desc function pointers and heap metadata (including the atoms pointer), providing controllable userspace memory corruption suitable for arbitrary write and code execution in the perf process.\nA:H - Pre-fix BUG_ON paths abort the perf process on allocation failure, and the heap out-of-bounds writes reliably crash or hang perf during register_pid() while parsing malicious perf.data."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-29T06:21:57.947Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/652cea73b7b7b7c622a2be670e44e3c499c6d49f"
        },
        {
          "url": "https://git.kernel.org/stable/c/5ea1dcc9418c4e06ce29ed5170596f497ba86872"
        },
        {
          "url": "https://git.kernel.org/stable/c/5949d339f5ec98752d56dcd4e36f619a59d513a5"
        }
      ],
      "title": "perf sched: Fix register_pid() overflow, strcpy, and BUG_ON",
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80671",
    "datePublished": "2026-08-28T06:49:11.744Z",
    "dateReserved": "2026-08-26T14:34:25.782Z",
    "dateUpdated": "2026-08-29T06:21:57.947Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
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      "date": "2026-09-01",
      "epss": "0.00157",
      "percentile": "0.05144"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-80671\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-28T08:16:52.410\",\"lastModified\":\"2026-08-29T07:16:49.477\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nperf sched: Fix register_pid() overflow, strcpy, and BUG_ON\\n\\nregister_pid() has several issues when processing untrusted perf.data:\\n\\n1. Integer overflow: (pid + 1) * sizeof(struct task_desc *) can wrap\\n   to a small value on 32-bit systems when pid is large (e.g.\\n   0x40000000), causing realloc to return a tiny buffer followed by\\n   out-of-bounds writes in the initialization loop.\\n\\n2. Heap buffer overflow: strcpy(task-\u003ecomm, comm) copies the\\n   untrusted comm string into a fixed 20-byte COMM_LEN buffer with\\n   no length check.\\n\\n3. BUG_ON on allocation failure: perf.data is untrusted input, so\\n   allocation failures should be handled gracefully rather than\\n   killing the process.\\n\\n4. Realloc of sched-\u003etasks assigned directly back, leaking the old\\n   pointer on failure; nr_tasks incremented before the realloc,\\n   leaving corrupted state on failure.\\n\\nCap pid at PID_MAX_LIMIT (4194304, matching the kernel\u0027s maximum\\non 64-bit), replace strcpy with strlcpy, guard against NULL comm,\\nreplace BUG_ON with NULL returns using safe realloc patterns, and\\nadd NULL checks in callers that dereference the result.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"tools/perf/builtin-sched.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"ec156764d424dd67283c2cd5e9f6f1b8388364ac\",\"lessThan\":\"652cea73b7b7b7c622a2be670e44e3c499c6d49f\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ec156764d424dd67283c2cd5e9f6f1b8388364ac\",\"lessThan\":\"5ea1dcc9418c4e06ce29ed5170596f497ba86872\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ec156764d424dd67283c2cd5e9f6f1b8388364ac\",\"lessThan\":\"5949d339f5ec98752d56dcd4e36f619a59d513a5\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"tools/perf/builtin-sched.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"2.6.32\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"2.6.32\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.40\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.5\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H\",\"baseScore\":9.3,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"CHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":2.5,\"impactScore\":6.0}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/5949d339f5ec98752d56dcd4e36f619a59d513a5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/5ea1dcc9418c4e06ce29ed5170596f497ba86872\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/652cea73b7b7b7c622a2be670e44e3c499c6d49f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-31T10:51:59+00:00",
      "cve": "CVE-2026-80671",
      "id": "CVE-2026-80671",
      "initial_release_date": "2026-08-28T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: perf sched: Fix register_pid() overflow, strcpy, and BUG_ON",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80671.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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