CVE-2026-98037 (GCVE-0-2026-98037)
Vulnerability from cvelistv5
Published
2026-09-25 10:23
Modified
2026-10-19 09:12
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Reject untrusted allocated-object pointers When the final RCU read-side critical section ends, a local kptr is demoted to PTR_UNTRUSTED but retains MEM_ALLOC. The pointer may be NULL or may refer to an object whose lifetime is no longer protected. type_is_ptr_alloc_obj() nevertheless recognizes any PTR_TO_BTF_ID with MEM_ALLOC as a live allocated object. In particular, a refcount-only local kptr never carries NON_OWN_REF, so it still passes the bpf_refcount_acquire() argument check after RCU protection ends. The kfunc can then dereference NULL or stale memory. Make type_is_ptr_alloc_obj() reject PTR_UNTRUSTED pointers. Since type_is_non_owning_ref() is based on the same predicate, graph kfunc arguments obey the same live-object requirement. Fault-protected reads of the demoted pointer remain valid: writes are already rejected, and read fixups use bpf_may_fault_on_deref() rather than this predicate. [ kkd: Rewrote commit log ]
References
Impacted products
Vendor Product Version
Linux Linux Version: 1b12171533a9bb23cf6fba7262b479028b65e1e8
Version: 1b12171533a9bb23cf6fba7262b479028b65e1e8
Version: 1b12171533a9bb23cf6fba7262b479028b65e1e8
Version: 1b12171533a9bb23cf6fba7262b479028b65e1e8
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/linux/bpf_verifier.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.8"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
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              "versionType": "semver"
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              "version": "7.2.7",
              "versionType": "semver"
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            {
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              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
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          "nodes": [
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              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.111",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "6.18.53",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                },
                {
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                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reject untrusted allocated-object pointers\n\nWhen the final RCU read-side critical section ends, a local kptr is demoted\nto PTR_UNTRUSTED but retains MEM_ALLOC. The pointer may be NULL or may refer\nto an object whose lifetime is no longer protected.\n\ntype_is_ptr_alloc_obj() nevertheless recognizes any PTR_TO_BTF_ID with\nMEM_ALLOC as a live allocated object. In particular, a refcount-only local\nkptr never carries NON_OWN_REF, so it still passes the\nbpf_refcount_acquire() argument check after RCU protection ends. The kfunc\ncan then dereference NULL or stale memory.\n\nMake type_is_ptr_alloc_obj() reject PTR_UNTRUSTED pointers. Since\ntype_is_non_owning_ref() is based on the same predicate, graph kfunc\narguments obey the same live-object requirement. Fault-protected reads of\nthe demoted pointer remain valid: writes are already rejected, and read\nfixups use bpf_may_fault_on_deref() rather than this predicate.\n\n[ kkd: Rewrote commit log ]"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:12:42.963Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/092c2874dc1b2060fa77a465a971acd4fdf87683"
        },
        {
          "url": "https://git.kernel.org/stable/c/135d542b97fa93e32c457d49d6e7b33ca7d05bae"
        },
        {
          "url": "https://git.kernel.org/stable/c/6b1f786ad85a0b63393b76f5e634deab1a73198c"
        },
        {
          "url": "https://git.kernel.org/stable/c/7441ee8276641bddaf1cba7bb75ef9c1458ceb3b"
        }
      ],
      "title": "bpf: Reject untrusted allocated-object pointers",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98037",
    "datePublished": "2026-09-25T10:23:51.126Z",
    "dateReserved": "2026-09-25T10:19:56.071Z",
    "dateUpdated": "2026-10-19T09:12:42.963Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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