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CVE-2026-72427 (GCVE-0-2026-72427)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:56 – Updated: 2026-08-17 05:44
VLAI
Title
bpf: Fix effective prog array index with BPF_F_PREORDER
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix effective prog array index with BPF_F_PREORDER replace_effective_prog() and purge_effective_progs() located the slot in the effective array by walking the program hlist and counting entries linearly. That count does not match the array layout: compute_effective_ progs() places BPF_F_PREORDER programs at the front (ancestor cgroup first, attach order within a cgroup) and the rest after them (descendant cgroup first). So when a preorder program is present, the linear hlist position no longer equals the program's index in the effective array. For replace_effective_prog() (bpf_link_update()) this overwrote the wrong slot, corrupting the effective order. For purge_effective_progs(), it could dummy out a slot belonging to a different program and leave the detached program in the array while bpf_prog_put() drops its reference, i.e. a use-after-free. Fix both by replaying compute_effective_progs()'s placement (including the per-cgroup preorder reversal) in a shared effective_prog_pos() helper. Identify the entry by its struct bpf_prog_list pointer rather than by (prog, link) value, so the lookup resolves to exactly the attachment the syscall selected even when the same bpf_prog is attached to several cgroups in the hierarchy.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: bc8023ef3b11410682e5d4990e05e5bc2d3e1c94 , < 525e408c27ae714e538b8c608c3a974df3ab6c92 (git)
Affected: 555c0b713ca83968d3c843cb15485b9ba3367b1b , < 41b4320b84fdafe1ab586b06453d30d50415db59 (git)
Affected: 4b82b181a26cff8bf7adc3a85a88d121d92edeaf , < 9697db03e010391c55ae75192cbdf30c5a72c114 (git)
Affected: 4b82b181a26cff8bf7adc3a85a88d121d92edeaf , < b584f107ab90222bd825dcb4c5977326ff684109 (git)
Affected: 4b82b181a26cff8bf7adc3a85a88d121d92edeaf , < f08aaee3152d0dfc578b3f2586932d82062701dd (git)
Affected: 4707ad649cf662add3058bff47430817811b048d (git)
Affected: 6.6.93 , < 6.6.145 (semver)
Affected: 6.12.31 , < 6.12.97 (semver)
Affected: 6.14.9 , < 6.15 (semver)
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Linux Linux Affected: 6.15
Unaffected: 0 , < 6.15 (semver)
Unaffected: 6.6.145 , ≤ 6.6.* (semver)
Unaffected: 6.12.97 , ≤ 6.12.* (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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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix effective prog array index with BPF_F_PREORDER\n\nreplace_effective_prog() and purge_effective_progs() located the slot in\nthe effective array by walking the program hlist and counting entries\nlinearly. That count does not match the array layout: compute_effective_\nprogs() places BPF_F_PREORDER programs at the front (ancestor cgroup\nfirst, attach order within a cgroup) and the rest after them (descendant\ncgroup first). So when a preorder program is present, the linear hlist\nposition no longer equals the program\u0027s index in the effective array.\n\nFor replace_effective_prog() (bpf_link_update()) this overwrote the\nwrong slot, corrupting the effective order. For purge_effective_progs(),\nit could dummy out a slot belonging to a different program and leave the\ndetached program in the array while bpf_prog_put() drops its reference,\ni.e. a use-after-free.\n\nFix both by replaying compute_effective_progs()\u0027s placement (including\nthe per-cgroup preorder reversal) in a shared effective_prog_pos()\nhelper. Identify the entry by its struct bpf_prog_list pointer rather\nthan by (prog, link) value, so the lookup resolves to exactly the\nattachment the syscall selected even when the same bpf_prog is attached\nto several cgroups in the hierarchy."
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    "cveId": "CVE-2026-72427",
    "datePublished": "2026-08-15T05:56:44.197Z",
    "dateReserved": "2026-08-09T03:40:39.928Z",
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-18T15:16:47+00:00",
      "cve": "CVE-2026-72427",
      "id": "CVE-2026-72427",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "184",
      "product_status:known_not_affected": "90",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: bpf: Fix effective prog array index with BPF_F_PREORDER",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72427.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.
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