CVE-2026-31570 (GCVE-0-2026-31570)

Vulnerability from cvelistv5 – Published: 2026-04-24 14:35 – Updated: 2026-04-24 14:35
VLAI?
Title
can: gw: fix OOB heap access in cgw_csum_crc8_rel()
Summary
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.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 456a8a646b2563438c16a9b27decf9aa717f1ebb , < e7c99348b0612b2bc02d5ce6ff9873261cc7605f (git)
Affected: 456a8a646b2563438c16a9b27decf9aa717f1ebb , < 999ca48d55a8a46da21519db7e834e5867200379 (git)
Affected: 456a8a646b2563438c16a9b27decf9aa717f1ebb , < a025283d7f7404c739225e457fb99db2368bb544 (git)
Affected: 456a8a646b2563438c16a9b27decf9aa717f1ebb , < 54ecdf76a55e75c1f5085e440f8ab671a3283ef5 (git)
Affected: 456a8a646b2563438c16a9b27decf9aa717f1ebb , < c4e8eaa75fa0b6bcbfa5356d6195c4ad0e05e57a (git)
Affected: 456a8a646b2563438c16a9b27decf9aa717f1ebb , < 84f8b76d24273175a22713e83e90874e1880d801 (git)
Affected: 456a8a646b2563438c16a9b27decf9aa717f1ebb , < 66b689efd08227da2c5ca49b58b30a95d23c695a (git)
Affected: 456a8a646b2563438c16a9b27decf9aa717f1ebb , < b9c310d72783cc2f30d103eed83920a5a29c671a (git)
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    Linux Linux Affected: 5.4
Unaffected: 0 , < 5.4 (semver)
Unaffected: 5.10.253 , ≤ 5.10.* (semver)
Unaffected: 5.15.203 , ≤ 5.15.* (semver)
Unaffected: 6.1.168 , ≤ 6.1.* (semver)
Unaffected: 6.6.131 , ≤ 6.6.* (semver)
Unaffected: 6.12.80 , ≤ 6.12.* (semver)
Unaffected: 6.18.21 , ≤ 6.18.* (semver)
Unaffected: 6.19.11 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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{
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncan: gw: fix OOB heap access in cgw_csum_crc8_rel()\n\ncgw_csum_crc8_rel() correctly computes bounds-safe indices via calc_idx():\n\n    int from = calc_idx(crc8-\u003efrom_idx, cf-\u003elen);\n    int to   = calc_idx(crc8-\u003eto_idx,   cf-\u003elen);\n    int res  = calc_idx(crc8-\u003eresult_idx, cf-\u003elen);\n\n    if (from \u003c 0 || to \u003c 0 || res \u003c 0)\n        return;\n\nHowever, the loop and the result write then use the raw s8 fields directly\ninstead of the computed variables:\n\n    for (i = crc8-\u003efrom_idx; ...)        /* BUG: raw negative index */\n    cf-\u003edata[crc8-\u003eresult_idx] = ...;    /* BUG: raw negative index */\n\nWith from_idx = to_idx = result_idx = -64 on a 64-byte CAN FD frame,\ncalc_idx(-64, 64) = 0 so the guard passes, but the loop iterates with\ni = -64, reading cf-\u003edata[-64], and the write goes to cf-\u003edata[-64].\nThis write might end up to 56 (7.0-rc) or 40 (\u003c= 6.19) bytes before the\nstart of the canfd_frame on the heap.\n\nThe companion function cgw_csum_xor_rel() uses `from`/`to`/`res`\ncorrectly throughout; fix cgw_csum_crc8_rel() to match.\n\nConfirmed with KASAN on linux-7.0-rc2:\n  BUG: KASAN: slab-out-of-bounds in cgw_csum_crc8_rel+0x515/0x5b0\n  Read of size 1 at addr ffff8880076619c8 by task poc_cgw_oob/62\n\nTo configure the can-gw crc8 checksums CAP_NET_ADMIN is needed."
        }
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        "dateUpdated": "2026-04-24T14:35:49.435Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/e7c99348b0612b2bc02d5ce6ff9873261cc7605f"
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          "url": "https://git.kernel.org/stable/c/999ca48d55a8a46da21519db7e834e5867200379"
        },
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          "url": "https://git.kernel.org/stable/c/a025283d7f7404c739225e457fb99db2368bb544"
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          "url": "https://git.kernel.org/stable/c/54ecdf76a55e75c1f5085e440f8ab671a3283ef5"
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          "url": "https://git.kernel.org/stable/c/c4e8eaa75fa0b6bcbfa5356d6195c4ad0e05e57a"
        },
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          "url": "https://git.kernel.org/stable/c/84f8b76d24273175a22713e83e90874e1880d801"
        },
        {
          "url": "https://git.kernel.org/stable/c/66b689efd08227da2c5ca49b58b30a95d23c695a"
        },
        {
          "url": "https://git.kernel.org/stable/c/b9c310d72783cc2f30d103eed83920a5a29c671a"
        }
      ],
      "title": "can: gw: fix OOB heap access in cgw_csum_crc8_rel()",
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    "cveId": "CVE-2026-31570",
    "datePublished": "2026-04-24T14:35:49.435Z",
    "dateReserved": "2026-03-09T15:48:24.117Z",
    "dateUpdated": "2026-04-24T14:35:49.435Z",
    "state": "PUBLISHED"
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      "date": "2026-04-25",
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      "percentile": "0.06802"
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  }
}


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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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