GHSA-GR2W-PHMC-QW83
Vulnerability from github – Published: 2026-08-10 15:33 – Updated: 2026-08-23 15:32In the Linux kernel, the following vulnerability has been resolved:
iomap: fix out-of-bounds bitmap_set() with zero-length range
ifs_set_range_dirty() and ifs_set_range_uptodate() compute last_blk as (off + len - 1) >> i_blkbits. When off is 0 and len is 0, the unsigned subtraction underflows to SIZE_MAX, producing a huge last_blk and nr_blks value that causes bitmap_set() to write far beyond the ifs->state allocation.
Regarding ifs_set_range_uptodate(), it is temporarily safe because len cannot be passed in as 0. However, for ifs_set_range_dirty() this is reachable from __iomap_write_end(): when copy_folio_from_iter_atomic() returns 0 (e.g. user buffer fault) and the folio is already uptodate, the guard at the top of __iomap_write_end() does not trigger because !folio_test_uptodate() is false, and iomap_set_range_dirty() is called with copied == 0.
Add a !len guard to both functions before the computation, so that a zero-length range is a no-op.
{
"affected": [],
"aliases": [
"CVE-2026-68145"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-10T13:20:00Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\niomap: fix out-of-bounds bitmap_set() with zero-length range\n\nifs_set_range_dirty() and ifs_set_range_uptodate() compute last_blk\nas (off + len - 1) \u003e\u003e i_blkbits. When off is 0 and len is 0, the\nunsigned subtraction underflows to SIZE_MAX, producing a huge\nlast_blk and nr_blks value that causes bitmap_set() to write far\nbeyond the ifs-\u003estate allocation.\n\nRegarding ifs_set_range_uptodate(), it is temporarily safe because len\ncannot be passed in as 0. However, for ifs_set_range_dirty() this is\nreachable from __iomap_write_end(): when copy_folio_from_iter_atomic()\nreturns 0 (e.g. user buffer fault) and the folio is already uptodate,\nthe guard at the top of __iomap_write_end() does not trigger because\n!folio_test_uptodate() is false, and iomap_set_range_dirty() is called\nwith copied == 0.\n\nAdd a !len guard to both functions before the computation, so that a\nzero-length range is a no-op.",
"id": "GHSA-gr2w-phmc-qw83",
"modified": "2026-08-23T15:32:56Z",
"published": "2026-08-10T15:33:37Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-68145"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/48829622212f6b8f49155889aecc818ba28ba680"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7037e7bdcd26f46c080b8ce307dee5cb471c4b7c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9c7d8f7c8994c790fca501dc45ce66e7356cbe05"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c5b6a48a8a716a7730e39af1cad083dc4ec955ce"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fb4fad9105c88b1d82f1b3c39e3b6abea8249af6"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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