{"cve":"CVE-2025-21919","nvd":{"published":"2025-04-01T16:15:22.557","modified":"2026-10-15T02:17:41.593","status":"Modified","description":"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 'prev' pointer to a cfs_rq.\nThis 'prev' pointer can originate from struct rq's 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->leaf_cfs_rq_list and rq->leaf_cfs_rq_list are added to the same\nleaf list. Also, rq->tmp_alone_branch can be set to rq->leaf_cfs_rq_list.\n\nThis adds a check `if (prev == &rq->leaf_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 'prev' pointer against the current rq's 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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":["CWE-787"],"references":["https://git.kernel.org/stable/c/000c9ee43928f2ce68a156dd40bab7616256f4dd","https://git.kernel.org/stable/c/3b4035ddbfc8e4521f85569998a7569668cccf51","https://git.kernel.org/stable/c/5cb300dcdd27e6a351ac02541e0231261c775852","https://git.kernel.org/stable/c/9cc7f0018609f75a349e42e3aebc3b0e905ba775","https://git.kernel.org/stable/c/b5741e4b9ef3567613b2351384f91d3f16e59986"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:00:57.946988208+00:00"},"epss":{"cve":"CVE-2025-21919","score":0.00237,"percentile":0.14585,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}