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bpf: Fix divide-by-zero in btf_struct_walk()

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix divide-by-zero in btf_struct_walk() When an access goes past the struct and the last member is a flexible array, btf_struct_walk() folds the offset back into a single element with (off - moff) % t->size, but never checks that the element type has a size. BTF takes an empty struct, so this in program BTF /* event could be empty */ struct event { #ifdef HAVE_TIMESTAMP __u64 ts; #endif }; struct batch { int nr; struct event events[]; }; divides by zero at prog load time. Getting there needs a PTR_TO_BTF_ID that is not MEM_ALLOC, e.g. a plain read of a local kptr stashed in a map from a sleepable program. Oops: divide error: 0000 [#1] SMP KASAN PTI RIP: 0010:btf_struct_walk+0x53f/0x1570 Call Trace: btf_struct_access+0x42a/0xcd0 check_ptr_to_btf_access+0x4dc/0x1160 check_mem_access+0x3a45/0x8740 check_load_mem+0x36a/0xd10 do_check_common+0x3ef0/0xb210 bpf_check+0x6d3b/0x8580 bpf_prog_load+0xf7c/0x2720 __sys_bpf+0xa83/0x3690 __x64_sys_bpf+0xc7/0x150 x64_sys_call+0x1f3f/0x27e0 do_syscall_64+0xe5/0x610 entry_SYSCALL_64_after_hwframe+0x76/0x7e Reject a zero-sized element type. The fixed array path in the same function already bails out on the same thing: btf_struct_walk() ... /* skip empty array */ if (moff == mtrue_end) continue; msize /= total_nelems;

Announced Source revision 1
Original source ↗

CVE-2026-98647

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-98647

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
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Prerequisites
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Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "9c5f8a1008a121e4c6b24af211034e24b0b63081",
        "lessThan": "1ea3820937f8022e044c41c6e95c84b02741b45f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9c5f8a1008a121e4c6b24af211034e24b0b63081",
        "lessThan": "172756f02663ad45c889c001c1a8cb4082a01a05",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9c5f8a1008a121e4c6b24af211034e24b0b63081",
        "lessThan": "934e9ba9f8d05656a48624710be67ca4dc8482e6",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9c5f8a1008a121e4c6b24af211034e24b0b63081",
        "lessThan": "63af086cb5fa6f72fd924f86bea4c2194da663a2",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9c5f8a1008a121e4c6b24af211034e24b0b63081",
        "lessThan": "8eb4cd72daad3a9ee63d2281bbdd16ce6d9406b1",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9c5f8a1008a121e4c6b24af211034e24b0b63081",
        "lessThan": "b8fa56722e9c43bcd59c51fe4c7edd5f4158a11b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9c5f8a1008a121e4c6b24af211034e24b0b63081",
        "lessThan": "b0b3dc66529676228cb938cbcad66920f735c223",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "kernel/bpf/btf.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.8"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.8",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.15.222",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.189",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.158",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.112",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.55",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.9",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "kernel/bpf/btf.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-98647

Source reference: /cveMetadata/cveId

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Event
#38667 · Revision 1
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