GHSA-C924-P67M-48HP
Vulnerability from github – Published: 2025-04-01 18:30 – Updated: 2026-07-14 15:31In the Linux kernel, the following vulnerability has been resolved:
sched/fair: Fix potential memory corruption in child_cfs_rq_on_list
child_cfs_rq_on_list attempts to convert a 'prev' pointer to a cfs_rq. This 'prev' pointer can originate from struct rq's leaf_cfs_rq_list, making the conversion invalid and potentially leading to memory corruption. Depending on the relative positions of leaf_cfs_rq_list and the task group (tg) pointer within the struct, this can cause a memory fault or access garbage data.
The issue arises in list_add_leaf_cfs_rq, where both cfs_rq->leaf_cfs_rq_list and rq->leaf_cfs_rq_list are added to the same leaf list. Also, rq->tmp_alone_branch can be set to rq->leaf_cfs_rq_list.
This adds a check if (prev == &rq->leaf_cfs_rq_list) after the main
conditional in child_cfs_rq_on_list. This ensures that the container_of
operation will convert a correct cfs_rq struct.
This check is sufficient because only cfs_rqs on the same CPU are added to the list, so verifying the 'prev' pointer against the current rq's list head is enough.
Fixes a potential memory corruption issue that due to current struct layout might not be manifesting as a crash but could lead to unpredictable behavior when the layout changes.
{
"affected": [],
"aliases": [
"CVE-2025-21919"
],
"database_specific": {
"cwe_ids": [
"CWE-787"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-04-01T16:15:22Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched/fair: Fix potential memory corruption in child_cfs_rq_on_list\n\nchild_cfs_rq_on_list attempts to convert a \u0027prev\u0027 pointer to a cfs_rq.\nThis \u0027prev\u0027 pointer can originate from struct rq\u0027s leaf_cfs_rq_list,\nmaking the conversion invalid and potentially leading to memory\ncorruption. Depending on the relative positions of leaf_cfs_rq_list and\nthe task group (tg) pointer within the struct, this can cause a memory\nfault or access garbage data.\n\nThe issue arises in list_add_leaf_cfs_rq, where both\ncfs_rq-\u003eleaf_cfs_rq_list and rq-\u003eleaf_cfs_rq_list are added to the same\nleaf list. Also, rq-\u003etmp_alone_branch can be set to rq-\u003eleaf_cfs_rq_list.\n\nThis adds a check `if (prev == \u0026rq-\u003eleaf_cfs_rq_list)` after the main\nconditional in child_cfs_rq_on_list. This ensures that the container_of\noperation will convert a correct cfs_rq struct.\n\nThis check is sufficient because only cfs_rqs on the same CPU are added\nto the list, so verifying the \u0027prev\u0027 pointer against the current rq\u0027s list\nhead is enough.\n\nFixes a potential memory corruption issue that due to current struct\nlayout might not be manifesting as a crash but could lead to unpredictable\nbehavior when the layout changes.",
"id": "GHSA-c924-p67m-48hp",
"modified": "2026-07-14T15:31:20Z",
"published": "2025-04-01T18:30:51Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-21919"
},
{
"type": "WEB",
"url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/000c9ee43928f2ce68a156dd40bab7616256f4dd"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3b4035ddbfc8e4521f85569998a7569668cccf51"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5cb300dcdd27e6a351ac02541e0231261c775852"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9cc7f0018609f75a349e42e3aebc3b0e905ba775"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b5741e4b9ef3567613b2351384f91d3f16e59986"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e1dd09df30ba86716cb2ffab97dc35195c01eb8f"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html"
}
],
"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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