CVE-2025-21704

Description

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"). 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.

Gravité et risque d'exploitation

CVE-2025-21704 obtient un score CVSS de 0.0/10, soit une gravité non évaluée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.37 %, ce qui la place devant 29.1 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <90dd2f1b7342b9a671a5ea4160f408037b92b118, <=6.1.*, <=6.12.*, <383d516a0ebc8641372b521c8cb717f0f1834831, 2.6.12, 0, <2.6.12, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 6.14, <=5.10.*, <=6.6.*, 6.1.129, <6abb510251e75f875797d8983a830e6731fa281c, <a4e1ae5c0533964170197e4fb4f33bc8c1db5cd2, 6.12.16, <=5.4.*, 5.4.291, <871619c2b78fdfe05afb4e8ba548678687beb812, 6.13.4, 5.15.179, <7828e9363ac4d23b02419bf2a45b9f1d9fb35646, <=*, <=5.15.*, 5.10.235, <=6.13.*, <f64079bef6a8a7823358c3f352ea29a617844636, <e563b01208f4d1f609bcab13333b6c0e24ce6a01, 6.6.79) est présent sur votre parc.
• Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
• À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
• Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

• https://git.kernel.org/stable/c/a4e1ae5c0533964170197e4fb4f33bc8c1db5cd2
• https://git.kernel.org/stable/c/90dd2f1b7342b9a671a5ea4160f408037b92b118
• https://git.kernel.org/stable/c/871619c2b78fdfe05afb4e8ba548678687beb812
• https://git.kernel.org/stable/c/7828e9363ac4d23b02419bf2a45b9f1d9fb35646
• https://git.kernel.org/stable/c/6abb510251e75f875797d8983a830e6731fa281c
• https://git.kernel.org/stable/c/f64079bef6a8a7823358c3f352ea29a617844636
• https://git.kernel.org/stable/c/383d516a0ebc8641372b521c8cb717f0f1834831
• https://git.kernel.org/stable/c/e563b01208f4d1f609bcab13333b6c0e24ce6a01
• https://project-zero.issues.chromium.org/issues/395107243