CVE-2022-49955 [Medium] | Security Vulnerability in Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: powerpc/rtas: Fix RTAS MSR[HV] handling for Cell The semi-recent changes to MSR handling when entering RTAS (firmware) cause crashes on IBM Cell machines. An example trace: kernel tried to execute user page (2fff01a8) - exploit attempt? (uid: 0) BUG: Unable to handle kernel instruction fetch Faulting instruction address: 0x2fff01a8 Oops: Kernel access of bad area, sig: 11 [#1] BE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=4 NUMA Cell Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 6.0.0-rc2-00433-gede0a8d3307a #207 NIP: 000000002fff01a8 LR: 0000000000032608 CTR: 0000000000000000 REGS: c0000000015236b0 TRAP: 0400 Tainted: G W (6.0.0-rc2-00433-gede0a8d3307a) MSR: 0000000008001002 <ME,RI> CR: 00000000 XER: 20000000 ... NIP 0x2fff01a8 LR 0x32608 Call Trace: 0xc00000000143c5f8 (unreliable) .rtas_call+0x224/0x320 .rtas_get_boot_time+0x70/0x150 .read_persistent_clock64+0x114/0x140 .read_persistent_wall_and_boot_offset+0x24/0x80 .timekeeping_init+0x40/0x29c .start_kernel+0x674/0x8f0 start_here_common+0x1c/0x50 Unlike PAPR platforms where RTAS is only used in guests, on the IBM Cell machines Linux runs with MSR[HV] set but also uses RTAS, provided by SLOF. Fix it by copying the MSR[HV] bit from the MSR value we've just read using mfmsr into the value used for RTAS. It seems like we could also fix it using an #ifdef CELL to set MSR[HV], but that doesn't work because it's possible to build a single kernel image that runs on both Cell native and pseries.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.07%	0.18%	+0.10%
2	2026-04-14	0.02%	0.07%	+0.06%
3	2025-06-18	—	0.02%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.07%

0.18%

+0.10%

2026-04-14

0.02%

0.07%

+0.06%

2025-06-18

—

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]

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-2022-49955

vendor	priority	summary	link
`debian`	unimportant	CVE-2022-49955 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-2022-49955
`redhat`	low	—	https://access.redhat.com/security/cve/CVE-2022-49955
`suse`	medium	CVE-2022-49955 severity moderate: SUSE including 26 source package names (cluster-md-kmp-default, dlm-kmp-default, …), 266 product×package rows across 52 product lines (SLES-LTSS-TERADATA 15 SP2, SUSE Linux Enterprise High Availability Extension 15 SP7, … (52 product lines)): Known Not Affected 266.	https://www.suse.com/security/cve/CVE-2022-49955/
`ubuntu`	medium	CVE-2022-49955 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, ignored 147, not-affected 134, released 92, needed 33.	https://ubuntu.com/security/CVE-2022-49955

Affected software / configurations for CVE-2022-49955

Vendor	Product	Version	Raw CPE
linux	linux_kernel	>= 5.15.46, < 5.16	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.17.14, < 5.18	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.18.3, < 5.19.8	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	6.0	cpe:2.3:o:linux:linux_kernel:6.0:rc1::::::
linux	linux_kernel	6.0	cpe:2.3:o:linux:linux_kernel:6.0:rc2::::::
linux	linux_kernel	6.0	cpe:2.3:o:linux:linux_kernel:6.0:rc3::::::

References for CVE-2022-49955

URL	Tags
https://git.kernel.org/stable/c/8b08d4f97233d8e58fff2fd9d5f86397a49733c5	Patch
https://git.kernel.org/stable/c/91926d8b7e71aaf5f84f0cf208fc5a8b7a761050	Patch

URL

CVE-2022-49955 | powerpc/rtas: Fix RTAS MSR[HV] handling for Cell

Exploit prediction scoring system (EPSS) score for CVE-2022-49955

Common vulnerability scoring system (CVSS) metrics for CVE-2022-49955

Weakness enumeration for CVE-2022-49955

OS Trackers for CVE-2022-49955

Affected software / configurations for CVE-2022-49955

References for CVE-2022-49955