GHSA-H6WW-MGJ9-P3PF
Vulnerability from github – Published: 2026-09-04 18:31 – Updated: 2026-09-04 18:31In the Linux kernel, the following vulnerability has been resolved:
nilfs2: reject invalid block index in GC ioctl
Syzbot reported list corruption caused by a double list_add_tail() call on bh->b_assoc_buffers within nilfs_lookup_dirty_data_buffers().
Analysis revealed that the root cause was the insertion of a page/folio with a page index of ULONG_MAX into the page cache via the GC ioctl. filemap_get_folios_tag(), called by nilfs_lookup_dirty_data_buffers(), repeatedly detects a dirty folio with a page index of ULONG_MAX due to index wrap-around, leading to duplicate processing of dirty buffers.
As a preparatory step, the GC ioctl loads the page/folio of the block to be moved during GC and inserts it into the page cache based on information in the nilfs_vdesc structure passed as an argument. Normally, this does not cause issues because the user-space GC library configures the nilfs_vdesc structure properly. However, since there is no range check on the parameters determining the page index, a request with artificially crafted parameters -- such as those generated by Syzbot -- can result in a page/folio being inserted with a page index of ULONG_MAX, triggering the above problem.
This resolves the issue by checking the ranges of 'vd_offset' and 'vd_vblocknr' in the nilfs_vdesc structure that determine the page index, thereby preventing the invalid page/folio insertions.
{
"affected": [],
"aliases": [
"CVE-2026-80807"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-04T16:18:07Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnilfs2: reject invalid block index in GC ioctl\n\nSyzbot reported list corruption caused by a double list_add_tail() call on\nbh-\u003eb_assoc_buffers within nilfs_lookup_dirty_data_buffers().\n\nAnalysis revealed that the root cause was the insertion of a page/folio\nwith a page index of ULONG_MAX into the page cache via the GC ioctl.\nfilemap_get_folios_tag(), called by nilfs_lookup_dirty_data_buffers(),\nrepeatedly detects a dirty folio with a page index of ULONG_MAX due to\nindex wrap-around, leading to duplicate processing of dirty buffers.\n\nAs a preparatory step, the GC ioctl loads the page/folio of the block to\nbe moved during GC and inserts it into the page cache based on information\nin the nilfs_vdesc structure passed as an argument. Normally, this does\nnot cause issues because the user-space GC library configures the\nnilfs_vdesc structure properly. However, since there is no range check on\nthe parameters determining the page index, a request with artificially\ncrafted parameters -- such as those generated by Syzbot -- can result in a\npage/folio being inserted with a page index of ULONG_MAX, triggering the\nabove problem.\n\nThis resolves the issue by checking the ranges of \u0027vd_offset\u0027 and\n\u0027vd_vblocknr\u0027 in the nilfs_vdesc structure that determine the page index,\nthereby preventing the invalid page/folio insertions.",
"id": "GHSA-h6ww-mgj9-p3pf",
"modified": "2026-09-04T18:31:27Z",
"published": "2026-09-04T18:31:27Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80807"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3bd064ccc70b85f9a3d53aece29dc8473be5a226"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/68aa9ab6f8f2895713aa6ddf781463ed8ea5ba44"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/898404cdf882d7b54f1132f75570984ca3214796"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a1735eae55448bc79c2da6593455791e886f6ed8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a5e776e2937581d67ec5b9b4d27b0f70d7baa6b1"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ba8a8b563a28d358c45c62a306d421434a058648"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e447f7edb99bd00cec63d6f3049e2e5074946f71"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ec6ddf271dfa4c7e3147bc2c8b2bad4315f316a1"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fbcfb75c20d71a5b542ad4ac3b79d10b997c8152"
}
],
"schema_version": "1.4.0",
"severity": []
}
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