GHSA-JW6Q-QFR2-5F75
Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-15 06:32In the Linux kernel, the following vulnerability has been resolved:
afs: Remove setting of AS_RELEASE_ALWAYS for symlinks and mountpoints
Regular AFS files correctly use afs_file_aops which have release_folio set as netfs_release_folio, so AS_RELEASE_ALWAYS is valid for them when fscache is enabled (set via afs_vnode_set_cache()). Symlinks and mountpoints in AFS use afs_dir_aops, which does not provide a release_folio callback. However, afs_apply_status() unconditionally calls mapping_set_release_always() for these.
In such case when memory management code attempts to release folios, filemap_release_folio() checks folio_needs_release() which returns true due to AS_RELEASE_ALWAYS being set. Since there is no release_folio callback, it falls through to try_to_free_buffers(), which at present expects buffer_heads to be not null. For symlinks and mountpoints without buffer_heads, this causes pointer dereference.
[dh: Added more bits that were missed]
{
"affected": [],
"aliases": [
"CVE-2026-72377"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-15T06:22:11Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nafs: Remove setting of AS_RELEASE_ALWAYS for symlinks and mountpoints\n\nRegular AFS files correctly use afs_file_aops which have release_folio\nset as netfs_release_folio, so AS_RELEASE_ALWAYS is valid for them\nwhen fscache is enabled (set via afs_vnode_set_cache()).\nSymlinks and mountpoints in AFS use afs_dir_aops, which does not provide\na release_folio callback. However, afs_apply_status() unconditionally\ncalls mapping_set_release_always() for these.\n\nIn such case when memory management code attempts to release folios,\nfilemap_release_folio() checks folio_needs_release() which\nreturns true due to AS_RELEASE_ALWAYS being set. Since there is no\nrelease_folio callback, it falls through to try_to_free_buffers(),\nwhich at present expects buffer_heads to be not null. For symlinks\nand mountpoints without buffer_heads, this causes pointer dereference.\n\n[dh: Added more bits that were missed]",
"id": "GHSA-jw6q-qfr2-5f75",
"modified": "2026-08-15T06:32:22Z",
"published": "2026-08-15T06:32:22Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72377"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/81e985b4c3a6cbcc443fcdcd3ebda7fcc845d459"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9d6b0f6d437e2f8350e08678e5e1d20c11c364f3"
}
],
"schema_version": "1.4.0",
"severity": []
}
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