CVE-2026-93144 (GCVE-0-2026-93144)
Vulnerability from cvelistv5
Published
2026-09-17 16:11
Modified
2026-10-21 12:52
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Reject writes through untrusted BTF pointers check_ptr_to_btf_access() lets program-type btf_struct_access callbacks validate writes before the default BTF access path rejects non-read accesses. That bypasses the read-only policy for untrusted BTF pointers created by helpers such as bpf_rdonly_cast(). Reject non-read accesses through PTR_UNTRUSTED BTF pointers at the common entry point, before the callback branch to handle all cases.
References
Impacted products
Vendor Product Version
Linux Linux Version: 282de143ead96a5d53331e946f31c977b4610a74
Version: 282de143ead96a5d53331e946f31c977b4610a74
Version: 282de143ead96a5d53331e946f31c977b4610a74
Version: 282de143ead96a5d53331e946f31c977b4610a74
Version: 282de143ead96a5d53331e946f31c977b4610a74
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/bpf/verifier.c"
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/bpf/verifier.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.2"
            },
            {
              "lessThan": "6.2",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.114",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.57",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.160",
                  "versionStartIncluding": "6.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.114",
                  "versionStartIncluding": "6.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.57",
                  "versionStartIncluding": "6.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.6",
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reject writes through untrusted BTF pointers\n\ncheck_ptr_to_btf_access() lets program-type btf_struct_access callbacks\nvalidate writes before the default BTF access path rejects non-read\naccesses. That bypasses the read-only policy for untrusted BTF pointers\ncreated by helpers such as bpf_rdonly_cast().\n\nReject non-read accesses through PTR_UNTRUSTED BTF pointers at the\ncommon entry point, before the callback branch to handle all cases."
        }
      ],
      "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 attacker-controlled input is BPF bytecode that calls bpf_rdonly_cast() then STX, submitted via bpf(BPF_PROG_LOAD) in SYSCALL_DEFINE5(bpf) \u2192 bpf_prog_load() \u2192 bpf_check() \u2192 do_check_main() \u2192 check_mem_access() \u2192 check_ptr_to_btf_access(); no remote protocol carries that untrusted pointer or the store.\nAC:L - A BPF_PROG_TYPE_STRUCT_OPS program attached to bpf_dummy_ops (check_struct_ops_btf_id() sets env-\u003eops to bpf_dummy_ops_btf_struct_access) or a BPF_PROG_TYPE_SCHED_CLS program (tc_cls_act_btf_struct_access) does bpf_rdonly_cast() then a store; the WRITE path ran the callback before the old \"only read is supported\" check. No race.\nPR:L - check_ptr_to_btf_access() returns -EPERM unless env-\u003eallow_ptr_leaks (bpf_token_capable(CAP_PERFMON)); STRUCT_OPS also fails is_perfmon_prog_type() without CAP_PERFMON, and add_subprog_and_kfunc() needs env-\u003ebpf_capable to emit bpf_rdonly_cast. bpf_token_capable() uses ns_capable() on a delegated token userns, not init-namespace root.\nUI:N - The attacker loads that program with BPF_PROG_LOAD and runs it via BPF_PROG_TEST_RUN (bpf_struct_ops_test_run() \u2192 dummy_ops_call_op() for bpf_dummy_ops, or bpf_prog_test_run_skb() for SCHED_CLS). No other user must mount, open a file, or cooperate.\nS:U - bpf_convert_ctx_accesses() leaves PTR_TO_BTF_ID|PTR_UNTRUSTED stores as plain STX (only reads become BPF_PROBE_MEM), so the write corrupts host kernel memory in the same authority as the bpf() caller; this is not a KVM/Xen guest-to-host escape or IOMMU bypass.\nC:H - The accepted STX writes attacker bytes through a bpf_rdonly_cast() pointer (obj__ign skips type checks) at bpf_dummy_ops_state.val, nf_conn.mark, or tcp_sock.snd_cwnd. That type-confused kernel write is a memory-corruption primitive that can be turned into an arbitrary kernel read.\nI:H - bpf_dummy_ops_btf_struct_access() accepts any store within sizeof(struct bpf_dummy_ops_state), and _nf_conntrack_btf_struct_access() accepts nf_conn.mark, on a PTR_UNTRUSTED base from bpf_rdonly_cast(); the JIT emits a plain store to that address, an arbitrary kernel write usable for control-flow hijacking.\nA:H - The same unprobed STX to bpf_rdonly_cast(0, btf_id) or to an out-of-bounds map/stack address page-faults in kernel context during bpf_struct_ops_test_run()/bpf_prog_test_run_skb() and oopses/panics, and the attacker can repeat BPF_PROG_TEST_RUN at will."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-21T12:52:02.003Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/56f92fecd80419567288b7972caa90107033836e"
        },
        {
          "url": "https://git.kernel.org/stable/c/c4dc883447ae38c4e22a29cc016046fa65d88994"
        },
        {
          "url": "https://git.kernel.org/stable/c/644cf4e77c2770d4246f6d12f99bc80d253b0ec6"
        },
        {
          "url": "https://git.kernel.org/stable/c/19d5566b84ca1af0256d0d0003e1a081580c3ba3"
        },
        {
          "url": "https://git.kernel.org/stable/c/ac65c710cc643cbc52b899627577357867249530"
        }
      ],
      "title": "bpf: Reject writes through untrusted BTF pointers",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-93144",
    "datePublished": "2026-09-17T16:11:42.757Z",
    "dateReserved": "2026-09-17T16:02:15.088Z",
    "dateUpdated": "2026-10-21T12:52:02.003Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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