CVE-2025-21704usb: cdc-acm: Check control transfer buffer size before access
Updated under an hour ago ()
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It affects Linux and 2 other products. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 7.8 HIGH (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Modified
- Record last updated
- Oct 15, 2026
- First seen by InfoSec Signals
- Oct 15, 2026
Affected products
Linux Linux linux:linux (from the name) | from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before a4e1ae5c0533964170197e4fb4f33bc8c1db5cd2; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 90dd2f1b7342b9a671a5ea4160f408037b92b118; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 871619c2b78fdfe05afb4e8ba548678687beb812; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 7828e9363ac4d23b02419bf2a45b9f1d9fb35646; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 6abb510251e75f875797d8983a830e6731fa281c; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before f64079bef6a8a7823358c3f352ea29a617844636; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 383d516a0ebc8641372b521c8cb717f0f1834831; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before e563b01208f4d1f609bcab13333b6c0e24ce6a01 | CNA record |
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem siemens:simatic_s7_1500_tm_mfp_gnu_linux_subsystem (from the name) | all versions | CISA ADP |
linux linux_kernel linux:linux_kernel | from 2.6.13 before 5.4.291; from 5.5 before 5.10.235; from 5.11 before 5.15.179; from 5.16 before 6.1.129; from 6.2 before 6.6.79; from 6.7 before 6.12.16; from 6.13 before 6.13.4; 2.6.12; and 6 more ranges | NVD |
References
- https://git.kernel.org/stable/c/a4e1ae5c0533964170197e4fb4f33bc8c1db5cd2patch
- https://git.kernel.org/stable/c/90dd2f1b7342b9a671a5ea4160f408037b92b118patch
- https://git.kernel.org/stable/c/871619c2b78fdfe05afb4e8ba548678687beb812patch
- https://git.kernel.org/stable/c/7828e9363ac4d23b02419bf2a45b9f1d9fb35646patch
- https://git.kernel.org/stable/c/6abb510251e75f875797d8983a830e6731fa281cpatch
- https://git.kernel.org/stable/c/f64079bef6a8a7823358c3f352ea29a617844636patch
- https://git.kernel.org/stable/c/383d516a0ebc8641372b521c8cb717f0f1834831patch
- https://git.kernel.org/stable/c/e563b01208f4d1f609bcab13333b6c0e24ce6a01patch
- https://project-zero.issues.chromium.org/issues/395107243exploit, issue-tracking, third-party-advisory
- 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
- https://cert-portal.siemens.com/productcert/html/ssa-784472.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.