CVE-2025-21704
In the Linux kernel, the following vulnerability has been resolved:
usb: cdc-acm: Check control transfer buffer size before access
If the first fragment is shorter than struct usb_cdc_notification, we can't calculate an expected_size. Log an error and discard the notification instead of reading lengths from memory outside the received data, which can lead to memory corruption when the expected_size decreases between fragments, causing `expected_size - acm->nb_index` to wrap.
This issue has been present since the beginning of git history; however, it only leads to memory corruption since commit ea2583529cd1 ("cdc-acm: reassemble fragmented notifications").
Leer descripción completaMostrar menos
A mitigating factor is that acm_ctrl_irq() can only execute after userspace has opened /dev/ttyACM*; but if ModemManager is running, ModemManager will do that automatically depending on the USB device's vendor/product IDs and its other interfaces.
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: 0.36%
- Percentil entre todas las CVEs puntuadas: 27
- 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.
- Explotación
T1068Exploitation for Privilege Escalationprivilege escalation75 % - Impacto principal
T1059Command and Scripting Interpreterexecution60 % - Impacto secundario
T1565.001Stored Data Manipulationimpact65 %
Buffer overflow en controlador USB (CWE-787) con acceso local (AV:L/PR:L). Código ejecutable tras abrir /dev/ttyACM*, permitiendo escalada y corrupción de memoria con potencial ejecución de comandos.
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
- CWE-787
Referencias
- https://git.kernel.org/stable/c/383d516a0ebc8641372b521c8cb717f0f1834831
- https://git.kernel.org/stable/c/6abb510251e75f875797d8983a830e6731fa281c
- https://git.kernel.org/stable/c/7828e9363ac4d23b02419bf2a45b9f1d9fb35646
- https://git.kernel.org/stable/c/871619c2b78fdfe05afb4e8ba548678687beb812
- https://git.kernel.org/stable/c/90dd2f1b7342b9a671a5ea4160f408037b92b118
- https://git.kernel.org/stable/c/a4e1ae5c0533964170197e4fb4f33bc8c1db5cd2
- https://git.kernel.org/stable/c/e563b01208f4d1f609bcab13333b6c0e24ce6a01
- https://git.kernel.org/stable/c/f64079bef6a8a7823358c3f352ea29a617844636
- https://project-zero.issues.chromium.org/issues/395107243
- https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html
- https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html
- https://cert-portal.siemens.com/productcert/html/ssa-265688.html
JSON original (NVD)
Mostrar
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: cdc-acm: Check control transfer buffer size before access\n\nIf the first fragment is shorter than struct usb_cdc_notification, we can't\ncalculate an expected_size. Log an error and discard the notification\ninstead of reading lengths from memory outside the received data, which can\nlead to memory corruption when the expected_size decreases between\nfragments, causing `expected_size - acm->nb_index` to wrap.\n\nThis issue has been present since the beginning of git history; however,\nit only leads to memory corruption since commit ea2583529cd1\n(\"cdc-acm: reassemble fragmented notifications\").\n\nA mitigating factor is that acm_ctrl_irq() can only execute after userspace\nhas opened /dev/ttyACM*; but if ModemManager is running, ModemManager will\ndo that automatically depending on the USB device's vendor/product IDs and\nits other interfaces."
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