{"cve":"CVE-2022-48921","nvd":{"published":"2024-08-22T02:15:08.197","modified":"2026-06-17T05:16:37.260","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched/fair: Fix fault in reweight_entity\n\nSyzbot found a GPF in reweight_entity. This has been bisected to\ncommit 4ef0c5c6b5ba (\"kernel/sched: Fix sched_fork() access an invalid\nsched_task_group\")\n\nThere is a race between sched_post_fork() and setpriority(PRIO_PGRP)\nwithin a thread group that causes a null-ptr-deref in\nreweight_entity() in CFS. The scenario is that the main process spawns\nnumber of new threads, which then call setpriority(PRIO_PGRP, 0, -20),\nwait, and exit.  For each of the new threads the copy_process() gets\ninvoked, which adds the new task_struct and calls sched_post_fork()\nfor it.\n\nIn the above scenario there is a possibility that\nsetpriority(PRIO_PGRP) and set_one_prio() will be called for a thread\nin the group that is just being created by copy_process(), and for\nwhich the sched_post_fork() has not been executed yet. This will\ntrigger a null pointer dereference in reweight_entity(), as it will\ntry to access the run queue pointer, which hasn't been set.\n\nBefore the mentioned change the cfs_rq pointer for the task  has been\nset in sched_fork(), which is called much earlier in copy_process(),\nbefore the new task is added to the thread_group.  Now it is done in\nthe sched_post_fork(), which is called after that.  To fix the issue\nthe remove the update_load param from the update_load param() function\nand call reweight_task() only if the task flag doesn't have the\nTASK_NEW flag set.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H","score":4.7},"cwes":["CWE-362"],"references":["https://git.kernel.org/stable/c/13765de8148f71fa795e0a6607de37c49ea5915a","https://git.kernel.org/stable/c/589a954daab5e18399860b6c8ffaeaf79844eb20","https://git.kernel.org/stable/c/8f317cd888059c59e2fa924bf4b0957cfa53f78e","https://git.kernel.org/stable/c/e0bcd6b5779352aed88f2e538a82a39f1a7715bb"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:54:16.205165117+00:00"},"epss":{"cve":"CVE-2022-48921","score":0.00168,"percentile":0.06033,"date":"2026-10-31"},"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."]}