CVE-2024-49854
CVE-2024-49854 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-416.
Key facts
- Severity: High (CVSS 3.x base score 7.8)
- EPSS exploit prediction: 0% (12th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2024-43711
- Weakness: CWE-416
- Affected product: Linux Linux Kernel
- Published:
- Last modified:
Description
In the Linux kernel, the following vulnerability has been resolved: block, bfq: fix uaf for accessing waker_bfqq after splitting After commit 42c306ed7233 ("block, bfq: don't break merge chain in bfq_split_bfqq()"), if the current procress is the last holder of bfqq, the bfqq can be freed after bfq_split_bfqq(). Hence recored the bfqq and then access bfqq->waker_bfqq may trigger UAF. What's more, the waker_bfqq may in the merge chain of bfqq, hence just recored waker_bfqq is still not safe. Fix the problem by adding a helper bfq_waker_bfqq() to check if bfqq->waker_bfqq is in the merge chain, and current procress is the only holder.
Frequently asked questions
- What is CVE-2024-49854?
- In the Linux kernel, the following vulnerability has been resolved: block, bfq: fix uaf for accessing waker_bfqq after splitting After commit 42c306ed7233 ("block, bfq: don't break merge chain in bfq_split_bfqq()"), if the current procress is the last holder of bfqq, the bfqq can be freed after bfq_split_bfqq(). Hence recored the bfqq and then access bfqq->waker_bfqq may trigger UAF. What's more, the waker_bfqq may in the merge chain of bfqq, hence just recored waker_bfqq is still not safe. Fix the problem by adding a helper bfq_waker_bfqq() to check if bfqq->waker_bfqq is in the merge chain, and current procress is the only holder.
- How severe is CVE-2024-49854?
- CVE-2024-49854 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2024-49854 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2024-49854?
- CVE-2024-49854 affects Linux Linux Kernel. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2024-49854?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2024-49854 have an EU (EUVD) identifier?
- Yes. CVE-2024-49854 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-43711.
- When was CVE-2024-49854 published?
- CVE-2024-49854 was published on 2024-10-21 and last updated on 2026-06-17.
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
- https://git.kernel.org/stable/c/de0456460f2abf921e356ed2bd8da87a376680bd
- https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html
Affected products (1)
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
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