CVE-2026-63864 (GCVE-0-2026-63864)

Vulnerability from cvelistv5 – Published: 2026-07-19 14:04 – Updated: 2026-08-05 12:36
VLAI
Title
bpf: Propagate error from visit_tailcall_insn
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Propagate error from visit_tailcall_insn Commit e40f5a6bf88a ("bpf: correct stack liveness for tail calls") added visit_tailcall_insn() but did not check its return value.
Severity
8.4 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: e40f5a6bf88a781d5f81bc6b8aab9ac31d8c98dd , < 945816e63c8677cf4bfde963a0774432ce8afc85 (git)
Affected: e40f5a6bf88a781d5f81bc6b8aab9ac31d8c98dd , < 6bd96e40f31dde8f8cd79772b4df0f171cf8a915 (git)
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Linux Linux Affected: 6.19
Unaffected: 0 , < 6.19 (semver)
Unaffected: 7.0.10 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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      "affected": [
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          "product": "Linux",
          "programFiles": [
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            "version": "3.1"
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              "value": "AV:L - The bug is reached only through the bpf() syscall during BPF_PROG_LOAD verification (check_cfg/visit_insn), which is a local kernel interface per kernel CVSS guidance for BPF.\nAC:L - An attacker can craft a BPF program using tail calls and subprograms to hit visit_tailcall_insn(), and can pressure kernel memory (parallel BPF loads/maps) to make the small jt allocation fail while verification continues.\nPR:N - Exploitation occurs at BPF_PROG_LOAD time via bpf(); on systems with kernel.unprivileged_bpf_disabled=0, unprivileged users can load socket-filter programs with PROG_ARRAY maps and tail calls without CAP_BPF or root.\nUI:N - No victim interaction is required; the attacker triggers the flaw by loading a malicious BPF program through their own bpf() syscall.\nS:U - Impact is a BPF verifier bypass leading to kernel memory corruption and local privilege escalation within the same kernel security boundary, not a cross-authority escape such as VM guest-to-host.\nC:H - Incorrect tail-call stack liveness lets verifier-approved programs perform out-of-bounds stack reads at runtime, exposing adjacent kernel stack memory and enabling arbitrary kernel memory disclosure primitives.\nI:H - The verifier bypass permits out-of-bounds stack writes and type confusion on stack slots, which can be leveraged for control-flow hijacking and arbitrary kernel code execution from BPF context.\nA:H - Out-of-bounds BPF stack access can trigger kernel oops/panic during program execution, and repeated exploitation can be used for denial of service even when full exploitation is not attempted."
            }
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        }
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      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:36:40.261Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/945816e63c8677cf4bfde963a0774432ce8afc85"
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        {
          "url": "https://git.kernel.org/stable/c/6bd96e40f31dde8f8cd79772b4df0f171cf8a915"
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    "cveId": "CVE-2026-63864",
    "datePublished": "2026-07-19T14:04:50.605Z",
    "dateReserved": "2026-07-19T07:54:57.017Z",
    "dateUpdated": "2026-08-05T12:36:40.261Z",
    "state": "PUBLISHED"
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      "percentile": "0.06815"
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            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Propagate error from visit_tailcall_insn\n\nCommit e40f5a6bf88a (\"bpf: correct stack liveness for tail calls\") added\nvisit_tailcall_insn() but did not check its return value."
          }
        ],
        "id": "CVE-2026-63864",
        "lastModified": "2026-07-27T17:44:23.777",
        "metrics": {
          "cvssMetricV31": [
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                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
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              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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        "vulnStatus": "Awaiting Analysis"
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      "cve": "CVE-2026-63864",
      "id": "CVE-2026-63864",
      "initial_release_date": "2026-07-19T00:00:00+00:00",
      "product_status:known_affected": "76",
      "product_status:known_not_affected": "198",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: bpf: Propagate error from visit_tailcall_insn",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63864.json",
      "version": "3"
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      "current_release_date": "2026-09-15T01:58:43Z",
      "cve": "CVE-2026-63864",
      "id": "CVE-2026-63864",
      "initial_release_date": "2026-07-24T16:21:44Z",
      "product_status:known_affected": "29",
      "product_status:known_not_affected": "347",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-63864",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-63864.json",
      "version": "4"
    }
  }
}



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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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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.