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can: gw: fix OOB heap access in cgw_csum_crc8_rel()

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: can: gw: fix OOB heap access in cgw_csum_crc8_rel() cgw_csum_crc8_rel() correctly computes bounds-safe indices via calc_idx(): int from = calc_idx(crc8->from_idx, cf->len); int to = calc_idx(crc8->to_idx, cf->len); int res = calc_idx(crc8->result_idx, cf->len); if (from < 0 || to < 0 || res < 0) return; However, the loop and the result write then use the raw s8 fields directly instead of the computed variables: for (i = crc8->from_idx; ...) /* BUG: raw negative index */ cf->data[crc8->result_idx] = ...; /* BUG: raw negative index */ With from_idx = to_idx = result_idx = -64 on a 64-byte CAN FD frame, calc_idx(-64, 64) = 0 so the guard passes, but the loop iterates with i = -64, reading cf->data[-64], and the write goes to cf->data[-64]. This write might end up to 56 (7.0-rc) or 40 (<= 6.19) bytes before the start of the canfd_frame on the heap. The companion function cgw_csum_xor_rel() uses `from`/`to`/`res` correctly throughout; fix cgw_csum_crc8_rel() to match. Confirmed with KASAN on linux-7.0-rc2: BUG: KASAN: slab-out-of-bounds in cgw_csum_crc8_rel+0x515/0x5b0 Read of size 1 at addr ffff8880076619c8 by task poc_cgw_oob/62 To configure the can-gw crc8 checksums CAP_NET_ADMIN is needed.

Announced Source revision 1
Original source ↗

CVE-2026-31570

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-2026-31570

Linux

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

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
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": "456a8a646b2563438c16a9b27decf9aa717f1ebb",
        "lessThan": "e7c99348b0612b2bc02d5ce6ff9873261cc7605f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "456a8a646b2563438c16a9b27decf9aa717f1ebb",
        "lessThan": "999ca48d55a8a46da21519db7e834e5867200379",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "456a8a646b2563438c16a9b27decf9aa717f1ebb",
        "lessThan": "a025283d7f7404c739225e457fb99db2368bb544",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "456a8a646b2563438c16a9b27decf9aa717f1ebb",
        "lessThan": "54ecdf76a55e75c1f5085e440f8ab671a3283ef5",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "456a8a646b2563438c16a9b27decf9aa717f1ebb",
        "lessThan": "c4e8eaa75fa0b6bcbfa5356d6195c4ad0e05e57a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "456a8a646b2563438c16a9b27decf9aa717f1ebb",
        "lessThan": "84f8b76d24273175a22713e83e90874e1880d801",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "456a8a646b2563438c16a9b27decf9aa717f1ebb",
        "lessThan": "66b689efd08227da2c5ca49b58b30a95d23c695a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "456a8a646b2563438c16a9b27decf9aa717f1ebb",
        "lessThan": "b9c310d72783cc2f30d103eed83920a5a29c671a",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/can/gw.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.4"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.4",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.253",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.203",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.168",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.131",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.80",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.21",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "6.19.11",
        "versionType": "semver",
        "lessThanOrEqual": "6.19.*"
      },
      {
        "status": "unaffected",
        "version": "7.0",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/can/gw.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-31570

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#39925 · Revision 1
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Publisher date
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