{"id":"CVE-2025-21919","title":"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 orig…","summary":"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 orig…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-787"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 5.13, < 5.15.179","linux_kernel >= 5.16, < 6.1.131","linux_kernel >= 6.2, < 6.6.83","linux_kernel >= 6.7, < 6.12.19","linux_kernel >= 6.13, < 6.13.7","linux_kernel = 6.14"],"patched":["linux_kernel 6.13.7"],"published":"2025-04-01","updated":"2026-07-14","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-21919","references":[{"url":"https://git.kernel.org/stable/c/000c9ee43928f2ce68a156dd40bab7616256f4dd","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3b4035ddbfc8e4521f85569998a7569668cccf51","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5cb300dcdd27e6a351ac02541e0231261c775852","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9cc7f0018609f75a349e42e3aebc3b0e905ba775","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b5741e4b9ef3567613b2351384f91d3f16e59986","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e1dd09df30ba86716cb2ffab97dc35195c01eb8f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","cve.org"],"epss":0.00228,"epssPercentile":0.13874,"ingestedAt":"2026-07-14T13:36:56.052Z","ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2025-10-01T19:23:59.713530Z"},"slug":"CVE-2025-21919","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `linux_kernel >= 5.13, < 5.15.179`\n- `linux_kernel >= 5.16, < 6.1.131`\n- `linux_kernel >= 6.2, < 6.6.83`\n- `linux_kernel >= 6.7, < 6.12.19`\n- `linux_kernel >= 6.13, < 6.13.7`\n- `linux_kernel = 6.14`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.13.7`","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}