CVE-2026-43424
CVE-2026-43424 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.
Key facts
- Severity: Medium (CVSS 3.x base score 5.5)
- EPSS exploit prediction: 0% (2nd percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-28730
- Weakness: CWE-476
- Affected product: Linux Linux Kernel
- Published:
- Last modified:
Description
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_tcm: Fix NULL pointer dereferences in nexus handling The `tpg->tpg_nexus` pointer in the USB Target driver is dynamically managed and tied to userspace configuration via ConfigFS. It can be NULL if the USB host sends requests before the nexus is fully established or immediately after it is dropped. Currently, functions like `bot_submit_command()` and the data transfer paths retrieve `tv_nexus = tpg->tpg_nexus` and immediately dereference `tv_nexus->tvn_se_sess` without any validation. If a malicious or misconfigured USB host sends a BOT (Bulk-Only Transport) command during this race window, it triggers a NULL pointer dereference, leading to a kernel panic (local DoS). This exposes an inconsistent API usage within the module, as peer functions like `usbg_submit_command()` and `bot_send_bad_response()` correctly implement a NULL check for `tv_nexus` before proceeding. Fix this by bringing consistency to the nexus handling. Add the missing `if (!tv_nexus)` checks to the vulnerable BOT command and request processing paths, aborting the command gracefully with an error instead of crashing the system.
Frequently asked questions
- What is CVE-2026-43424?
- In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_tcm: Fix NULL pointer dereferences in nexus handling The `tpg->tpg_nexus` pointer in the USB Target driver is dynamically managed and tied to userspace configuration via ConfigFS. It can be NULL if the USB host sends requests before the nexus is fully established or immediately after it is dropped. Currently, functions like `bot_submit_command()` and the data transfer paths retrieve `tv_nexus = tpg->tpg_nexus` and immediately dereference `tv_nexus->tvn_se_sess` without any validation. If a malicious or misconfigured USB host sends a BOT (Bulk-Only Transport) command during this race window, it triggers a NULL pointer dereference, leading to a kernel panic (local DoS). This exposes an inconsistent API usage within the module, as peer functions like `usbg_submit_command()` and `bot_send_bad_response()` correctly implement a NULL check for `tv_nexus` before proceeding. Fix this by bringing consistency to the nexus handling. Add the missing `if (!tv_nexus)` checks to the vulnerable BOT command and request processing paths, aborting the command gracefully with an error instead of crashing the system.
- How severe is CVE-2026-43424?
- CVE-2026-43424 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2026-43424 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-43424?
- CVE-2026-43424 primarily affects Linux Linux Kernel. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2026-43424?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2026-43424 have an EU (EUVD) identifier?
- Yes. CVE-2026-43424 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-28730.
- When was CVE-2026-43424 published?
- CVE-2026-43424 was published on 2026-05-08 and last updated on 2026-06-17.
References
- https://git.kernel.org/stable/c/2a2ef846a54a06c33b5c2d4b0d918583e1e7c0b7
- https://git.kernel.org/stable/c/3d309b37633c4a847fc149939a2c9576f1aa1065
- https://git.kernel.org/stable/c/679d9535aeb15c10bce89c44102004b96624d706
- https://git.kernel.org/stable/c/b9b26d7f3aa288cfa54a7bc68612bab1f153f156
- https://git.kernel.org/stable/c/b9fde507355342a2d64225d582dc8b98ff5ecb19
- https://git.kernel.org/stable/c/d146f27758049fa55ae4c53785a852d3cf7a18d6
- https://git.kernel.org/stable/c/f962ca3b020e13d6714f27e8c36fe742441c58d1
Affected products (5)
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*
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