ghsa-9j3f-w66p-jqvg
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
arm64: kexec: initialize kexec_buf struct in load_other_segments()
Patch series "kexec: Fix invalid field access".
The kexec_buf structure was previously declared without initialization. commit bf454ec31add ("kexec_file: allow to place kexec_buf randomly") added a field that is always read but not consistently populated by all architectures. This un-initialized field will contain garbage.
This is also triggering a UBSAN warning when the uninitialized data was accessed:
------------[ cut here ]------------
UBSAN: invalid-load in ./include/linux/kexec.h:210:10
load of value 252 is not a valid value for type '_Bool'
Zero-initializing kexec_buf at declaration ensures all fields are cleanly set, preventing future instances of uninitialized memory being used.
An initial fix was already landed for arm64[0], and this patchset fixes the problem on the remaining arm64 code and on riscv, as raised by Mark.
Discussions about this problem could be found at[1][2].
This patch (of 3):
The kexec_buf structure was previously declared without initialization. commit bf454ec31add ("kexec_file: allow to place kexec_buf randomly") added a field that is always read but not consistently populated by all architectures. This un-initialized field will contain garbage.
This is also triggering a UBSAN warning when the uninitialized data was accessed:
------------[ cut here ]------------
UBSAN: invalid-load in ./include/linux/kexec.h:210:10
load of value 252 is not a valid value for type '_Bool'
Zero-initializing kexec_buf at declaration ensures all fields are cleanly set, preventing future instances of uninitialized memory being used.
{
"affected": [],
"aliases": [
"CVE-2025-39904"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-10-01T08:15:33Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\narm64: kexec: initialize kexec_buf struct in load_other_segments()\n\nPatch series \"kexec: Fix invalid field access\".\n\nThe kexec_buf structure was previously declared without initialization. \ncommit bf454ec31add (\"kexec_file: allow to place kexec_buf randomly\")\nadded a field that is always read but not consistently populated by all\narchitectures. This un-initialized field will contain garbage.\n\nThis is also triggering a UBSAN warning when the uninitialized data was\naccessed:\n\n\t------------[ cut here ]------------\n\tUBSAN: invalid-load in ./include/linux/kexec.h:210:10\n\tload of value 252 is not a valid value for type \u0027_Bool\u0027\n\nZero-initializing kexec_buf at declaration ensures all fields are cleanly\nset, preventing future instances of uninitialized memory being used.\n\nAn initial fix was already landed for arm64[0], and this patchset fixes\nthe problem on the remaining arm64 code and on riscv, as raised by Mark.\n\nDiscussions about this problem could be found at[1][2].\n\n\nThis patch (of 3):\n\nThe kexec_buf structure was previously declared without initialization.\ncommit bf454ec31add (\"kexec_file: allow to place kexec_buf randomly\")\nadded a field that is always read but not consistently populated by all\narchitectures. This un-initialized field will contain garbage.\n\nThis is also triggering a UBSAN warning when the uninitialized data was\naccessed:\n\n\t------------[ cut here ]------------\n\tUBSAN: invalid-load in ./include/linux/kexec.h:210:10\n\tload of value 252 is not a valid value for type \u0027_Bool\u0027\n\nZero-initializing kexec_buf at declaration ensures all fields are\ncleanly set, preventing future instances of uninitialized memory being\nused.",
"id": "GHSA-9j3f-w66p-jqvg",
"modified": "2025-10-01T09:30:24Z",
"published": "2025-10-01T09:30:24Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-39904"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/04d3cd43700a2d0fe4bfb1012a8ec7f2e34a3507"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/340cc9a3bd30b25edaf6a9708d41b5f2c10a054a"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
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