CVE-2022-49554 [Medium] | Security Vulnerability in Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: zsmalloc: fix races between asynchronous zspage free and page migration The asynchronous zspage free worker tries to lock a zspage's entire page list without defending against page migration. Since pages which haven't yet been locked can concurrently migrate off the zspage page list while lock_zspage() churns away, lock_zspage() can suffer from a few different lethal races. It can lock a page which no longer belongs to the zspage and unsafely dereference page_private(), it can unsafely dereference a torn pointer to the next page (since there's a data race), and it can observe a spurious NULL pointer to the next page and thus not lock all of the zspage's pages (since a single page migration will reconstruct the entire page list, and create_page_chain() unconditionally zeroes out each list pointer in the process). Fix the races by using migrate_read_lock() in lock_zspage() to synchronize with page migration.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.02%	0.18%	+0.16%
2	2025-10-23	0.05%	0.02%	-0.03%
3	2025-05-05	—	0.05%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.02%

0.18%

+0.16%

2025-10-23

0.05%

0.02%

-0.03%

2025-05-05

—

0.05%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
4.7	3.1	MEDIUM	`CVSS:3.1/AV:L/AC:H/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:H) Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work. 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.	1.0	3.6	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

4.7

3.1

MEDIUM

CVSS:3.1/AV:L/AC:H/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:H): Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
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.

1.0

3.6

[email protected]

OS Trackers for CVE-2022-49554

vendor	priority	summary	link
`debian`	not yet assigned	CVE-2022-49554 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-2022-49554
`redhat`	low	—	https://access.redhat.com/security/cve/CVE-2022-49554
`suse`	medium	CVE-2022-49554 severity moderate: SUSE including 25 source package names (cluster-md-kmp-default, dlm-kmp-default, …), 160 product×package rows across 28 product lines (SUSE Linux Enterprise High Availability Extension 12 SP5, SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS, … (28 product lines)): Known Not Affected 160.	https://www.suse.com/security/cve/CVE-2022-49554/
`ubuntu`	medium	CVE-2022-49554 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 1551 status rows across 10 suites (bionic, focal, jammy, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 1145, released 151, ignored 146, not-affected 109.	https://ubuntu.com/security/CVE-2022-49554

Affected software / configurations for CVE-2022-49554

Vendor	Product	Version	Raw CPE
linux	linux_kernel	>= 4.14, < 4.14.282	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 4.15, < 4.19.246	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 4.20, < 5.4.197	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.5, < 5.10.120	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.11, < 5.15.45	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.16, < 5.17.13	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.18, < 5.18.2	cpe:2.3:o:linux:linux_kernel::::::::

References for CVE-2022-49554

URL	Tags
https://git.kernel.org/stable/c/2505a981114dcb715f8977b8433f7540854851d8	Patch
https://git.kernel.org/stable/c/3674d8a8dadd03a447dd21069d4dacfc3399b63b	Patch
https://git.kernel.org/stable/c/3ec459c8810e658401be428d3168eacfc380bdd0	Patch
https://git.kernel.org/stable/c/645996efc2ae391246d595832aaa6f9d3cc338c7	Patch
https://git.kernel.org/stable/c/8ba7b7c1dad1f6503c541778f31b33f7f62eb966	Patch
https://git.kernel.org/stable/c/c5402fb5f71f1a725f1e55d9c6799c0c7bec308f	Patch
https://git.kernel.org/stable/c/fae05b2314b147a78fbed1dc4c645d9a66313758	Patch
https://git.kernel.org/stable/c/fc658c083904427abbf8f18280d517ee2668677c	Patch

URL

CVE-2022-49554 | zsmalloc: fix races between asynchronous zspage free and page migration

Exploit prediction scoring system (EPSS) score for CVE-2022-49554

Common vulnerability scoring system (CVSS) metrics for CVE-2022-49554

Weakness enumeration for CVE-2022-49554

OS Trackers for CVE-2022-49554

Affected software / configurations for CVE-2022-49554

References for CVE-2022-49554