CVE-2024-49854

block, bfq: fix uaf for accessing waker_bfqq after splitting

Severity Score

7.1

*CVSS v3

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Track

*SSVC

Descriptions

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.

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.

These are all security issues fixed in the kernel-devel-longterm-6.12.11-1.1 package on the GA media of openSUSE Tumbleweed.

*Credits: N/A

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

High

Attack Vector

Network

Attack Complexity

Low

Authentication

None

Confidentiality

Partial

Integrity

None

Availability

None

* Common Vulnerability Scoring System

SSVC

Decision:Track

Exploitation

None

Automatable

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2024-10-21 CVE Reserved
2024-10-21 CVE Published
2026-05-11 CVE Updated
2026-05-11 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CAPEC

References (9)

URL	Tag	Source
https://git.kernel.org/stable/c/9e813033594b141f61ff0ef0cfaaef292564b041	Vuln. Introduced
https://git.kernel.org/stable/c/3a5f45a4ad4e1fd36b0a998eef03d76a4f02a2a8	Vuln. Introduced
https://git.kernel.org/stable/c/3630a18846c7853aa326d3b42fd0a855af7b41bc	Vuln. Introduced

URL	Date	SRC

URL	Date	SRC
https://git.kernel.org/stable/c/63a07379fdb6c72450cb05294461c6016b8b7726	2024-10-17
https://git.kernel.org/stable/c/de0456460f2abf921e356ed2bd8da87a376680bd	2024-10-17
https://git.kernel.org/stable/c/0780451f03bf518bc032a7c584de8f92e2d39d7f	2024-10-04
https://git.kernel.org/stable/c/0b8bda0ff17156cd3f60944527c9d8c9f99f1583	2024-10-04
https://git.kernel.org/stable/c/cae58d19121a70329cf971359e2518c93fec04fe	2024-10-04
https://git.kernel.org/stable/c/1ba0403ac6447f2d63914fb760c44a3b19c44eaf	2024-09-10

URL	Date	SRC

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				4.19.323 Search vendor "Linux" for product "Linux Kernel" and version "4.19.323"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				5.4.285 Search vendor "Linux" for product "Linux Kernel" and version "5.4.285"		en		Affected
Linux Search vendor "Linux"		Linux Kernel Search vendor "Linux" for product "Linux Kernel"				5.10.227 Search vendor "Linux" for product "Linux Kernel" and version "5.10.227"		en		Affected