{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/linux/bpf.h",
            "kernel/bpf/arraymap.c",
            "kernel/bpf/core.c",
            "kernel/bpf/syscall.c",
            "kernel/bpf/trampoline.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "987aa730bad3e1ef66d9f30182294daa78f6387d",
              "status": "affected",
              "version": "be8704ff07d2374bcc5c675526f95e70c6459683",
              "versionType": "git"
            },
            {
              "lessThan": "d6083f040d5d8f8d748462c77e90547097df936e",
              "status": "affected",
              "version": "be8704ff07d2374bcc5c675526f95e70c6459683",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "include/linux/bpf.h",
            "kernel/bpf/arraymap.c",
            "kernel/bpf/core.c",
            "kernel/bpf/syscall.c",
            "kernel/bpf/trampoline.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.6"
            },
            {
              "lessThan": "5.6",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.13",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.5",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.13",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Prevent tailcall infinite loop caused by freplace\n\nThere is a potential infinite loop issue that can occur when using a\ncombination of tail calls and freplace.\n\nIn an upcoming selftest, the attach target for entry_freplace of\ntailcall_freplace.c is subprog_tc of tc_bpf2bpf.c, while the tail call in\nentry_freplace leads to entry_tc. This results in an infinite loop:\n\nentry_tc -\u003e subprog_tc -\u003e entry_freplace --tailcall-\u003e entry_tc.\n\nThe problem arises because the tail_call_cnt in entry_freplace resets to\nzero each time entry_freplace is executed, causing the tail call mechanism\nto never terminate, eventually leading to a kernel panic.\n\nTo fix this issue, the solution is twofold:\n\n1. Prevent updating a program extended by an freplace program to a\n   prog_array map.\n2. Prevent extending a program that is already part of a prog_array map\n   with an freplace program.\n\nThis ensures that:\n\n* If a program or its subprogram has been extended by an freplace program,\n  it can no longer be updated to a prog_array map.\n* If a program has been added to a prog_array map, neither it nor its\n  subprograms can be extended by an freplace program.\n\nMoreover, an extension program should not be tailcalled. As such, return\n-EINVAL if the program has a type of BPF_PROG_TYPE_EXT when adding it to a\nprog_array map.\n\nAdditionally, fix a minor code style issue by replacing eight spaces with a\ntab for proper formatting."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The entire attack is built and triggered through the local `bpf(2)` syscall \u2014 two `BPF_PROG_LOAD` calls, a `BPF_LINK_CREATE` freplace attach, a `PROG_ARRAY` map update, and `BPF_PROG_TEST_RUN`. No network peer or remote input is involved, and no netdev attachment is required.\nAC:L - The attacker constructs every component of the loop (target prog, its bpf2bpf subprog, the freplace extension, and the prog_array entry) and fires it deterministically; there is no race, no memory-layout dependency, and no state outside the attacker\u0027s control. Every invocation reproduces the runaway tail-call chain.\nPR:L - Loading `BPF_PROG_TYPE_EXT` goes through `bpf_token_capable()` for CAP_BPF/CAP_NET_ADMIN/CAP_PERFMON, which grants only `ns_capable()`-level checks when a BPF token is delegated to a user namespace via bpffs `delegate_cmds`/`delegate_progs` \u2014 so a low-privileged container process with a delegated token can reach it, and no real init-namespace root is strictly needed.\nUI:N - The attacker loads, attaches, and executes the programs entirely on its own via `BPF_PROG_TEST_RUN` or by attaching the classifier and sending itself a packet. No victim action of any kind is required.\nS:U - The corruption and the crash both occur in the kernel\u0027s own stack within the same security authority; there is no VM, IOMMU, or sandbox boundary crossed.\nC:H - The unbounded recursion is an out-of-bounds write past the kernel stack limit with attacker-chosen BPF stack contents; on builds without CONFIG_VMAP_STACK (e.g. KASAN_GENERIC configs, where `arch/Kconfig` disables it) the overflow spills into adjacent kernel memory, yielding a corruption primitive usable for disclosing kernel data.\nI:H - Same stack overflow gives an unbounded, attacker-controlled out-of-bounds write past the stack guard limit, which on non-VMAP_STACK configurations overwrites adjacent kernel structures and is leverageable for control-flow hijack; per guidance any OOB write scores High.\nA:H - The commit states the tail-call mechanism \"never terminate[s], eventually leading to a kernel panic\" \u2014 the stack grows every cycle until it hits the guard page, producing an immediate double-fault panic (or silent corruption) within microseconds, and it can be re-triggered on every packet if the classifier is attached to a live interface."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T11:39:59.232Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/987aa730bad3e1ef66d9f30182294daa78f6387d"
        },
        {
          "url": "https://git.kernel.org/stable/c/d6083f040d5d8f8d748462c77e90547097df936e"
        }
      ],
      "title": "bpf: Prevent tailcall infinite loop caused by freplace",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2024-47794",
    "datePublished": "2025-01-11T12:25:14.419Z",
    "dateReserved": "2025-01-09T09:49:29.737Z",
    "dateUpdated": "2026-08-05T11:39:59.232Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}