CVE-2023-53445 [Medium] | Use-After-Free in Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: net: qrtr: Fix a refcount bug in qrtr_recvmsg() Syzbot reported a bug as following: refcount_t: addition on 0; use-after-free. ... RIP: 0010:refcount_warn_saturate+0x17c/0x1f0 lib/refcount.c:25 ... Call Trace: <TASK> __refcount_add include/linux/refcount.h:199 [inline] __refcount_inc include/linux/refcount.h:250 [inline] refcount_inc include/linux/refcount.h:267 [inline] kref_get include/linux/kref.h:45 [inline] qrtr_node_acquire net/qrtr/af_qrtr.c:202 [inline] qrtr_node_lookup net/qrtr/af_qrtr.c:398 [inline] qrtr_send_resume_tx net/qrtr/af_qrtr.c:1003 [inline] qrtr_recvmsg+0x85f/0x990 net/qrtr/af_qrtr.c:1070 sock_recvmsg_nosec net/socket.c:1017 [inline] sock_recvmsg+0xe2/0x160 net/socket.c:1038 qrtr_ns_worker+0x170/0x1700 net/qrtr/ns.c:688 process_one_work+0x991/0x15c0 kernel/workqueue.c:2390 worker_thread+0x669/0x1090 kernel/workqueue.c:2537 It occurs in the concurrent scenario of qrtr_recvmsg() and qrtr_endpoint_unregister() as following: cpu0 cpu1 qrtr_recvmsg qrtr_endpoint_unregister qrtr_send_resume_tx qrtr_node_release qrtr_node_lookup mutex_lock(&qrtr_node_lock) spin_lock_irqsave(&qrtr_nodes_lock, ) refcount_dec_and_test(&node->ref) [node->ref == 0] radix_tree_lookup [node != NULL] __qrtr_node_release qrtr_node_acquire spin_lock_irqsave(&qrtr_nodes_lock, ) kref_get(&node->ref) [WARNING] ... mutex_unlock(&qrtr_node_lock) Use qrtr_node_lock to protect qrtr_node_lookup() implementation, this is actually improving the protection of node reference.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2025-09-19	—	0.02%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2025-09-19

—

0.02%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
5.5	3.1	MEDIUM	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	1.8	3.6	[email protected]
5.5	3.1	MEDIUM	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	1.8	3.6	134c704f-9b21-4f2e-91b3-4a467353bcc0

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

5.5

3.1

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand

Attack vector (AV:L): They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L): A normal user session is enough; they don’t have to be admin.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

1.8

3.6

[email protected]

5.5

3.1

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand

Attack vector (AV:L): They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L): A normal user session is enough; they don’t have to be admin.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N): Doesn’t really leak secrets in a meaningful way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

1.8

3.6

134c704f-9b21-4f2e-91b3-4a467353bcc0

OS Trackers for CVE-2023-53445

vendor	priority	summary	link
`debian`	not yet assigned	CVE-2023-53445 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2023-53445
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2023-53445
`suse`	medium	CVE-2023-53445 severity moderate: SUSE including 26 source package names (cluster-md-kmp-default, dlm-kmp-default, …), 229 product×package rows across 44 product lines (SLES-LTSS-TERADATA 15 SP2, SUSE Linux Enterprise High Availability Extension 15 SP7, … (44 product lines)): Known Not Affected 229.	https://www.suse.com/security/cve/CVE-2023-53445/
`ubuntu`	medium	CVE-2023-53445 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 1414 status rows across 9 suites (bionic, focal, jammy, noble, plucky, questing, trusty, upstream, xenial): DNE 1017, ignored 158, not-affected 122, released 116, needs-triage 1.	https://ubuntu.com/security/CVE-2023-53445

Affected software / configurations for CVE-2023-53445

Vendor	Product	Version	Raw CPE
linux	linux_kernel	>= 5.6, < 5.10.178	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.11, < 5.15.107	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.16, < 6.1.24	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.2, < 6.2.11	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	6.3	cpe:2.3:o:linux:linux_kernel:6.3:rc1::::::
linux	linux_kernel	6.3	cpe:2.3:o:linux:linux_kernel:6.3:rc2::::::
linux	linux_kernel	6.3	cpe:2.3:o:linux:linux_kernel:6.3:rc3::::::
linux	linux_kernel	6.3	cpe:2.3:o:linux:linux_kernel:6.3:rc4::::::
linux	linux_kernel	6.3	cpe:2.3:o:linux:linux_kernel:6.3:rc5::::::

References for CVE-2023-53445

URL	Tags
https://git.kernel.org/stable/c/44d807320000db0d0013372ad39b53e12d52f758	Patch
https://git.kernel.org/stable/c/48a07f6e00d305597396da4d7494b81cec05b9d3	Patch
https://git.kernel.org/stable/c/98a9cd82c541ef6cbdb829cd6c05cbbb471e373c	Patch
https://git.kernel.org/stable/c/aa95efa187b4114075f312b3c4680d050b56fdec	Patch
https://git.kernel.org/stable/c/b9ba5906c42089f8e1d0001b7b50a7940f086cbb	Patch

URL

CVE-2023-53445 | net: qrtr: Fix a refcount bug in qrtr_recvmsg()

Exploit prediction scoring system (EPSS) score for CVE-2023-53445

Common vulnerability scoring system (CVSS) metrics for CVE-2023-53445

Weakness enumeration for CVE-2023-53445

OS Trackers for CVE-2023-53445

Affected software / configurations for CVE-2023-53445

References for CVE-2023-53445