{"cve":"CVE-2024-49854","nvd":{"published":"2024-10-21T13:15:06.203","modified":"2026-08-04T11:20:50.910","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nblock, bfq: fix uaf for accessing waker_bfqq after splitting\n\nAfter commit 42c306ed7233 (\"block, bfq: don't break merge chain in\nbfq_split_bfqq()\"), if the current procress is the last holder of bfqq,\nthe bfqq can be freed after bfq_split_bfqq(). Hence recored the bfqq and\nthen access bfqq->waker_bfqq may trigger UAF. What's more, the waker_bfqq\nmay in the merge chain of bfqq, hence just recored waker_bfqq is still\nnot safe.\n\nFix the problem by adding a helper bfq_waker_bfqq() to check if\nbfqq->waker_bfqq is in the merge chain, and current procress is the only\nholder.","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-416"],"references":["https://git.kernel.org/stable/c/0780451f03bf518bc032a7c584de8f92e2d39d7f","https://git.kernel.org/stable/c/0b8bda0ff17156cd3f60944527c9d8c9f99f1583","https://git.kernel.org/stable/c/1ba0403ac6447f2d63914fb760c44a3b19c44eaf","https://git.kernel.org/stable/c/63a07379fdb6c72450cb05294461c6016b8b7726","https://git.kernel.org/stable/c/cae58d19121a70329cf971359e2518c93fec04fe"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:56:33.105311382+00:00"},"epss":{"cve":"CVE-2024-49854","score":0.00215,"percentile":0.11969,"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."]}