CVE-2024-49854

block, bfq: fix uaf for accessing waker_bfqq after splitting

HIGH

7.8

CVSS Score

Published: October 21, 2024 at 12:18 PM UTC

Updated: August 4, 2026 at 04:06 PM UTC

1 product affected across 1 vendorLinux Kernel

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Severity

HIGH7.8

Exploit prediction

EPSS 0.2%

SSVC

No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Linux Kernel · Linux

95%

v ≥ 4.19.323v ≥ 5.10.227v ≥ 5.4.2854.19.323 ≤ v < 4.205.10.227 ≤ v < 5.115.10.227 ≤ v < 5.15.1685.16 ≤ v < 6.1.1135.4.285 ≤ v < 5.56.11 ≤ v < 6.11.26.2 ≤ v < 6.6.546.7 ≤ v < 6.10.1313b3d0e8cb121f99b11918a0d4bcc1ce4647d35219f3bec2ac4be329b9bd12b18a989b867618d2d83630a18846c7853aa326d3b42fd0a855af7b41bc3a5f45a4ad4e1fd36b0a998eef03d76a4f02a2a84.19.32342c306ed723321af4003b2a41bb73728cab54f854780f50ea50cfe8e89fc3747bf3dd155488433bb5.10.227 5.4.2859e813033594b141f61ff0ef0cfaaef292564b041de6c5e3a456019d2182e345730e59721714fa0b5e0c20d88b7dce85d2703bb6ba77bf359959675cd

Vendor states this is fixed in 0b8bda0ff17156cd3f60944527c9d8c9f99f1583 (fixed)

Vendor states this is fixed in 1ba0403ac6447f2d63914fb760c44a3b19c44eaf (fixed)

Vendor states this is fixed in 63a07379fdb6c72450cb05294461c6016b8b7726 (fixed)

Vendor states this is fixed in 780451f3bf518bc32a7c584de8f92e2d39d7f (fixed)

Vendor states this is fixed in cae58d19121a70329cf971359e2518c93fec04fe (fixed)

Vendor states this is fixed in de0456460f2abf921e356ed2bd8da87a376680bd (fixed)

Affected range stops below 4.20, so it looks safe — our inference, not a vendor statement

Affected range stops below 5.11, so it looks safe — our inference, not a vendor statement

Affected range stops below 5.15.168, so it looks safe — our inference, not a vendor statement

Affected range stops below 5.5, so it looks safe — our inference, not a vendor statement

Affected range stops below 6.1.113, so it looks safe — our inference, not a vendor statement

Affected range stops below 6.10.13, so it looks safe — our inference, not a vendor statement

Affected range stops below 6.11.2, so it looks safe — our inference, not a vendor statement

Affected range stops below 6.6.54, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references