CVE-2026-64293
In the Linux kernel, the following vulnerability has been resolved:
iommufd: Use sizeof(*hdr) instead of sizeof(hdr) in veventq read
The bound-check in iommufd_veventq_fops_read() for the normal vEVENT path uses sizeof(hdr) where the surrounding code uses sizeof(*hdr):
hdr is declared as struct iommufd_vevent_header *, so sizeof(hdr) evaluates to the size of the pointer. Surrounding code uses sizeof(*hdr) consistently:
struct iommufd_vevent_header is currently 8 bytes (two __u32 fields, flags and sequence), so on 64-bit (sizeof(void *) == 8) the two expressions happen to be equal and the check works as intended.
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On 32-bit (sizeof(void *) == 4) the check under-counts the header by 4 bytes: a vEVENT whose data_len causes 8 + cur->data_len to exceed count - done while 4 + cur->data_len does not will pass the check, then the loop will copy_to_user 8 bytes of header followed by data_len bytes of payload, writing past the user-supplied buffer.
It is also a latent bug for any future expansion of struct iommufd_vevent_header beyond sizeof(void *) on 64-bit; the check should not depend on the type happening to match the host pointer width.
Use sizeof(*hdr) to match the rest of the function and the actual amount that will be copied.
Detalles técnicos trazas, registros y código del informe original
if (!vevent_for_lost_events_header(cur) &&
sizeof(hdr) + cur->data_len > count - done) {
if (done >= count || sizeof(*hdr) > count - done) {
...
if (copy_to_user(buf + done, hdr, sizeof(*hdr))) {
...
done += sizeof(*hdr);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: 0.17%
- Percentil entre todas las CVEs puntuadas: 5
- 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).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1068Exploitation for Privilege Escalationprivilege escalation92 % - Impacto principal
T1059Command and Scripting Interpreterexecution78 % - Impacto secundario
T1499.004Application or System Exploitationimpact65 %
Acceso local (AV:L) sin interacción (UI:N) con privilegios (PR:L) en Linux kernel → T1068. Buffer overflow permite ejecución de código arbitrario y denegación de servicio.
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
Tecnologías afectadas (1)
CWE
- NVD-CWE-noinfo
Referencias
JSON original (NVD)
Mostrar
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}
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"lastModified": "2026-08-17T05:17:28.837",
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