CVE-2022-49081 [Medium] | Security Vulnerability in Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: highmem: fix checks in __kmap_local_sched_{in,out} When CONFIG_DEBUG_KMAP_LOCAL is enabled __kmap_local_sched_{in,out} check that even slots in the tsk->kmap_ctrl.pteval are unmapped. The slots are initialized with 0 value, but the check is done with pte_none. 0 pte however does not necessarily mean that pte_none will return true. e.g. on xtensa it returns false, resulting in the following runtime warnings: WARNING: CPU: 0 PID: 101 at mm/highmem.c:627 __kmap_local_sched_out+0x51/0x108 CPU: 0 PID: 101 Comm: touch Not tainted 5.17.0-rc7-00010-gd3a1cdde80d2-dirty #13 Call Trace: dump_stack+0xc/0x40 __warn+0x8f/0x174 warn_slowpath_fmt+0x48/0xac __kmap_local_sched_out+0x51/0x108 __schedule+0x71a/0x9c4 preempt_schedule_irq+0xa0/0xe0 common_exception_return+0x5c/0x93 do_wp_page+0x30e/0x330 handle_mm_fault+0xa70/0xc3c do_page_fault+0x1d8/0x3c4 common_exception+0x7f/0x7f WARNING: CPU: 0 PID: 101 at mm/highmem.c:664 __kmap_local_sched_in+0x50/0xe0 CPU: 0 PID: 101 Comm: touch Tainted: G W 5.17.0-rc7-00010-gd3a1cdde80d2-dirty #13 Call Trace: dump_stack+0xc/0x40 __warn+0x8f/0x174 warn_slowpath_fmt+0x48/0xac __kmap_local_sched_in+0x50/0xe0 finish_task_switch$isra$0+0x1ce/0x2f8 __schedule+0x86e/0x9c4 preempt_schedule_irq+0xa0/0xe0 common_exception_return+0x5c/0x93 do_wp_page+0x30e/0x330 handle_mm_fault+0xa70/0xc3c do_page_fault+0x1d8/0x3c4 common_exception+0x7f/0x7f Fix it by replacing !pte_none(pteval) with pte_val(pteval) != 0.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-04-11	0.08%	0.01%	-0.07%
2	2026-04-06	0.03%	0.08%	+0.05%
3	2025-11-21	—	0.03%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-04-11

0.08%

0.01%

-0.07%

2026-04-06

0.03%

0.08%

+0.05%

2025-11-21

—

0.03%

—

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]

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]

OS Trackers for CVE-2022-49081

vendor	priority	summary	link
`debian`	unimportant	CVE-2022-49081 unimportant 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-2022-49081
`redhat`	low	—	https://access.redhat.com/security/cve/CVE-2022-49081
`suse`	medium	CVE-2022-49081 severity moderate: SUSE including 73 source package names (bpftool-4.18.0-553.el8_10, bpftool-7.0.0-284.11.1.el9_2, …), 198 product×package rows across 32 product lines (SLES-LTSS-TERADATA 15 SP2, SUSE Liberty Linux 8, … (32 product lines)): Known Not Affected 151, Fixed 47.	https://www.suse.com/security/cve/CVE-2022-49081/
`ubuntu`	medium	CVE-2022-49081 medium priority: Ubuntu including 130 source packages (linux, linux-allwinner-5.19, …), 1040 status rows across 8 suites (bionic, focal, jammy, noble, oracular, trusty, upstream, xenial): DNE 713, ignored 146, not-affected 101, released 80.	https://ubuntu.com/security/CVE-2022-49081

Affected software / configurations for CVE-2022-49081

Vendor	Product	Version	Raw CPE
linux	linux_kernel	>= 5.11, < 5.15.34	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.16, < 5.16.20	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.17, < 5.17.3	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	5.18	cpe:2.3:o:linux:linux_kernel:5.18:rc1::::::

References for CVE-2022-49081

URL	Tags
https://git.kernel.org/stable/c/66f133ceab7456c789f70a242991ed1b27ba1c3d	Patch
https://git.kernel.org/stable/c/7dd5b3b97716a611fcf67d92fd2370fcb8d50372	Patch
https://git.kernel.org/stable/c/85550b0f5fa5dd3c30469ea702c44444ef242c83	Patch
https://git.kernel.org/stable/c/c21d040de6225414547d9bd31cd200f290991c85	Patch

URL

CVE-2022-49081 | highmem: fix checks in __kmap_local_sched_{in,out}

Exploit prediction scoring system (EPSS) score for CVE-2022-49081

Common vulnerability scoring system (CVSS) metrics for CVE-2022-49081

Weakness enumeration for CVE-2022-49081

OS Trackers for CVE-2022-49081

Affected software / configurations for CVE-2022-49081

References for CVE-2022-49081