CVE-2026-31570can: gw: fix OOB heap access in cgw_csum_crc8_rel()
Updated under an hour ago ()
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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.
- CVSS
- 8.8 HIGH (v3.1, CNA)CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Analyzed
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 456a8a646b2563438c16a9b27decf9aa717f1ebb before e7c99348b0612b2bc02d5ce6ff9873261cc7605f; from 456a8a646b2563438c16a9b27decf9aa717f1ebb before 999ca48d55a8a46da21519db7e834e5867200379; from 456a8a646b2563438c16a9b27decf9aa717f1ebb before a025283d7f7404c739225e457fb99db2368bb544; 456a8a646b2563438c16a9b27decf9aa717f1ebb builds before 54ecdf76a55e75c1f5085e440f8ab671a3283ef5; from 456a8a646b2563438c16a9b27decf9aa717f1ebb before c4e8eaa75fa0b6bcbfa5356d6195c4ad0e05e57a; 456a8a646b2563438c16a9b27decf9aa717f1ebb builds before 84f8b76d24273175a22713e83e90874e1880d801; 456a8a646b2563438c16a9b27decf9aa717f1ebb builds before 66b689efd08227da2c5ca49b58b30a95d23c695a; from 456a8a646b2563438c16a9b27decf9aa717f1ebb before b9c310d72783cc2f30d103eed83920a5a29c671a | CNA record |
linux linux_kernel linux:linux_kernel | from 5.4.1 before 5.10.253; from 5.11 before 5.15.203; from 5.16 before 6.1.168; from 6.2 before 6.6.131; from 6.7 before 6.12.80; from 6.13 before 6.18.21; from 6.19 before 6.19.11; 5.4; and 7 more ranges | NVD |
References
- https://git.kernel.org/stable/c/e7c99348b0612b2bc02d5ce6ff9873261cc7605fpatch
- https://git.kernel.org/stable/c/999ca48d55a8a46da21519db7e834e5867200379patch
- https://git.kernel.org/stable/c/a025283d7f7404c739225e457fb99db2368bb544patch
- https://git.kernel.org/stable/c/54ecdf76a55e75c1f5085e440f8ab671a3283ef5patch
- https://git.kernel.org/stable/c/c4e8eaa75fa0b6bcbfa5356d6195c4ad0e05e57apatch
- https://git.kernel.org/stable/c/84f8b76d24273175a22713e83e90874e1880d801patch
- https://git.kernel.org/stable/c/66b689efd08227da2c5ca49b58b30a95d23c695apatch
- https://git.kernel.org/stable/c/b9c310d72783cc2f30d103eed83920a5a29c671apatch
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.