CVE-2023-53272 [High] | Out-of-bounds Read in Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: net: ena: fix shift-out-of-bounds in exponential backoff The ENA adapters on our instances occasionally reset. Once recently logged a UBSAN failure to console in the process: UBSAN: shift-out-of-bounds in build/linux/drivers/net/ethernet/amazon/ena/ena_com.c:540:13 shift exponent 32 is too large for 32-bit type 'unsigned int' CPU: 28 PID: 70012 Comm: kworker/u72:2 Kdump: loaded not tainted 5.15.117 Hardware name: Amazon EC2 c5d.9xlarge/, BIOS 1.0 10/16/2017 Workqueue: ena ena_fw_reset_device [ena] Call Trace: <TASK> dump_stack_lvl+0x4a/0x63 dump_stack+0x10/0x16 ubsan_epilogue+0x9/0x36 __ubsan_handle_shift_out_of_bounds.cold+0x61/0x10e ? __const_udelay+0x43/0x50 ena_delay_exponential_backoff_us.cold+0x16/0x1e [ena] wait_for_reset_state+0x54/0xa0 [ena] ena_com_dev_reset+0xc8/0x110 [ena] ena_down+0x3fe/0x480 [ena] ena_destroy_device+0xeb/0xf0 [ena] ena_fw_reset_device+0x30/0x50 [ena] process_one_work+0x22b/0x3d0 worker_thread+0x4d/0x3f0 ? process_one_work+0x3d0/0x3d0 kthread+0x12a/0x150 ? set_kthread_struct+0x50/0x50 ret_from_fork+0x22/0x30 </TASK> Apparently, the reset delays are getting so large they can trigger a UBSAN panic. Looking at the code, the current timeout is capped at 5000us. Using a base value of 100us, the current code will overflow after (1<<29). Even at values before 32, this function wraps around, perhaps unintentionally. Cap the value of the exponent used for this backoff at (1<<16) which is larger than currently necessary, but large enough to support bigger values in the future.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2025-09-16	—	0.02%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2025-09-16

—

0.02%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
7.1	3.1	HIGH	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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:H) Serious risk that confidential data gets exposed in a big 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	5.2	[email protected]
7.1	3.1	HIGH	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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:H) Serious risk that confidential data gets exposed in a big 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	5.2	134c704f-9b21-4f2e-91b3-4a467353bcc0

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

7.1

3.1

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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:H): Serious risk that confidential data gets exposed in a big 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

5.2

[email protected]

7.1

3.1

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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:H): Serious risk that confidential data gets exposed in a big 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

5.2

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

OS Trackers for CVE-2023-53272

vendor	priority	summary	link
`debian`	not yet assigned	CVE-2023-53272 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-2023-53272
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2023-53272
`suse`	medium	—	https://www.suse.com/security/cve/CVE-2023-53272/
`ubuntu`	medium	CVE-2023-53272 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, released 116, not-affected 100, needed 22, needs-triage 1.	https://ubuntu.com/security/CVE-2023-53272

Affected software / configurations for CVE-2023-53272

Vendor	Product	Version	Raw CPE
linux	linux_kernel	>= 5.8, < 5.10.188	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.11, < 5.15.121	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.16, < 6.1.40	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.2, < 6.4.5	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	6.5	cpe:2.3:o:linux:linux_kernel:6.5:rc1::::::

References for CVE-2023-53272

URL	Tags
https://git.kernel.org/stable/c/0939c264729d4a081ff88efce2ffdf85dc5331e0	Patch
https://git.kernel.org/stable/c/1e760b2d18bf129b3da052c2946c02758e97d15e	Patch
https://git.kernel.org/stable/c/1e9cb763e9bacf0c932aa948f50dcfca6f519a26	Patch
https://git.kernel.org/stable/c/3e36cc94d6e60a27f27498adf1c71eeba769ab33	Patch
https://git.kernel.org/stable/c/90947ebf8794e3c229fb2e16e37f1bfea6877f14	Patch

URL

CVE-2023-53272 | net: ena: fix shift-out-of-bounds in exponential backoff

Exploit prediction scoring system (EPSS) score for CVE-2023-53272

Common vulnerability scoring system (CVSS) metrics for CVE-2023-53272

Weakness enumeration for CVE-2023-53272

OS Trackers for CVE-2023-53272

Affected software / configurations for CVE-2023-53272

References for CVE-2023-53272