{"cve":"CVE-2026-31570","nvd":{"published":"2026-04-24T15:16:31.520","modified":"2026-10-19T19:18:00.280","status":"Modified","description":"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->from_idx, cf->len);\n    int to   = calc_idx(crc8->to_idx,   cf->len);\n    int res  = calc_idx(crc8->result_idx, cf->len);\n\n    if (from < 0 || to < 0 || res < 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->from_idx; ...)        /* BUG: raw negative index */\n    cf->data[crc8->result_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->data[-64], and the write goes to cf->data[-64].\nThis write might end up to 56 (7.0-rc) or 40 (<= 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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":8.8},"cwes":["CWE-125","CWE-787"],"references":["https://git.kernel.org/stable/c/54ecdf76a55e75c1f5085e440f8ab671a3283ef5","https://git.kernel.org/stable/c/66b689efd08227da2c5ca49b58b30a95d23c695a","https://git.kernel.org/stable/c/84f8b76d24273175a22713e83e90874e1880d801","https://git.kernel.org/stable/c/999ca48d55a8a46da21519db7e834e5867200379","https://git.kernel.org/stable/c/a025283d7f7404c739225e457fb99db2368bb544"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-21T03:43:09.190223697+00:00"},"epss":{"cve":"CVE-2026-31570","score":0.00263,"percentile":0.17996,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}