CVE-2022-49955
Estado: AnalizadaMedia (5.5)—
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:
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.
Detalles técnicos trazas, registros y código del informe original
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/0x50CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Puntuación base: 5.5
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.20%
- Percentil entre todas las CVEs puntuadas: 9
- Fecha de la puntuación: 5/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
CWE
- CWE-476
Referencias
JSON original (NVD)
Mostrar
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/rtas: Fix RTAS MSR[HV] handling for Cell\n\nThe semi-recent changes to MSR handling when entering RTAS (firmware)\ncause crashes on IBM Cell machines. An example trace:\n\n kernel tried to execute user page (2fff01a8) - exploit attempt? (uid: 0)\n BUG: Unable to handle kernel instruction fetch\n Faulting instruction address: 0x2fff01a8\n Oops: Kernel access of bad area, sig: 11 [#1]\n BE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=4 NUMA Cell\n Modules linked in:\n CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 6.0.0-rc2-00433-gede0a8d3307a #207\n NIP: 000000002fff01a8 LR: 0000000000032608 CTR: 0000000000000000\n REGS: c0000000015236b0 TRAP: 0400 Tainted: G W (6.0.0-rc2-00433-gede0a8d3307a)\n MSR: 0000000008001002 <ME,RI> CR: 00000000 XER: 20000000\n ...\n NIP 0x2fff01a8\n LR 0x32608\n Call Trace:\n 0xc00000000143c5f8 (unreliable)\n .rtas_call+0x224/0x320\n .rtas_get_boot_time+0x70/0x150\n .read_persistent_clock64+0x114/0x140\n .read_persistent_wall_and_boot_offset+0x24/0x80\n .timekeeping_init+0x40/0x29c\n .start_kernel+0x674/0x8f0\n start_here_common+0x1c/0x50\n\nUnlike PAPR platforms where RTAS is only used in guests, on the IBM Cell\nmachines Linux runs with MSR[HV] set but also uses RTAS, provided by\nSLOF.\n\nFix it by copying the MSR[HV] bit from the MSR value we've just read\nusing mfmsr into the value used for RTAS.\n\nIt seems like we could also fix it using an #ifdef CELL to set MSR[HV],\nbut that doesn't work because it's possible to build a single kernel\nimage that runs on both Cell native and pseries."
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"value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: powerpc/rtas: Corrección del manejo de MSR[HV] de RTAS para Cell. Los cambios recientes en el manejo de MSR al ingresar RTAS (firmware) provocan bloqueos en las máquinas IBM Cell. Ejemplo de rastreo: el kernel intentó ejecutar la página de usuario (2fff01a8): ¿intento de explotación? (uid: 0) ERROR: No se puede controlar la obtención de instrucciones del núcleo Dirección de instrucción errónea: 0x2fff01a8 Oops: Acceso del núcleo al área defectuosa, firma: 11 [#1] BE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=4 Módulos de celda NUMA vinculados: CPU: 0 PID: 0 Comm: swapper/0 Contaminado: GW 6.0.0-rc2-00433-gede0a8d3307a #207 NIP: 000000002fff01a8 LR: 0000000000032608 CTR: 000000000000000 REGS: c0000000015236b0 TRAP: 0400 Contaminado: GW (6.0.0-rc2-00433-gede0a8d3307a) MSR: 0000000008001002 CR: 00000000 XER: 20000000 ... NIP 0x2fff01a8 LR 0x32608 Rastreo de llamadas: 0xc00000000143c5f8 (no confiable) .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 A diferencia de las plataformas PAPR, donde RTAS solo se usa en huéspedes, en las máquinas IBM Cell, Linux se ejecuta con MSR[HV] activado, pero también usa RTAS, proporcionado por SLOF. Para solucionarlo, copie el bit MSR[HV] del valor MSR que acabamos de leer con mfmsr al valor usado para RTAS. Parece que también podríamos solucionarlo usando un #ifdef CELL para activar MSR[HV], pero esto no funciona, ya que es posible crear una única imagen de kernel que funcione tanto en Cell nativo como en pseries."
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"lastModified": "2026-06-17T05:19:37.020",
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