medium CVSS 5.5 Actively exploited EPSS 1.3%

CVE-2024-50302·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: HID: core: zero-initialize the report buffer Since the report buffer is used by all kinds of drivers in various ways, let's zero-initialize it during allocation to make sure that it can't be ever used to leak kernel memory via specially-crafted report.

Severity
medium
Software
Kernel
Fixed in
6.11.8
Published

How likely is exploitation

FIRST's Exploit Prediction Scoring System puts the probability of this CVE being exploited in the next 30 days at 1.3% — higher than 80% of all published CVEs. EPSS is an independent forecast of exploitation, not a severity rating: it says nothing about how much damage a successful attack does, which is what a CVSS score measures.

Affected versions

From: 6.7

Until: 6.11.8

Fixed in: 6.11.8

How to fix this CVE

Update the Linux kernel to a patched version from your distribution. The fix adds zero-initialization of HID report buffers in the core HID layer. A reboot is required after kernel update.

sudo apt update && sudo apt install --only-upgrade linux-image-generic
# Verify: uname -r (should show patched version)
sudo reboot
# Check Ubuntu security notices: https://ubuntu.com/security/CVE-2024-50302

Defensia detects this vulnerability

What an exploitation attempt looks like

Sample log line indicative of exploitation attempts:

Local exploitation via crafted HID device interactions. The attacker opens and reads from HID device files (/dev/hidraw*) or uses the HIDIOCSFEATURE/HIDIOCGFEATURE ioctls to trigger report buffer allocation. Since the buffer is not zeroed, the read returns stale kernel heap data. In targeted attacks, this is chained with USB-based attacks or used by already-compromised local accounts for KASLR bypass.

WAF mitigation (if patching is not yet possible)

Add this rule to your WAF to block exploitation attempts while you schedule the patch. 

WAF rules cannot mitigate kernel memory disclosure vulnerabilities. Compensating controls include:
- Restrict access to /dev/hidraw* devices via udev rules
- Use kernel hardening: CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y
- Limit local user access to the system
- Disable unused HID drivers via module blacklisting

How to check if you are affected

  1. Check if your kernel includes the fix: grep -r 'zero-initialize.*report' /usr/src/linux*/drivers/hid/ 2>/dev/null || echo 'Check kernel changelog'
  2. Check kernel version against distribution security advisories
  3. List loaded HID modules: lsmod | grep hid
  4. Check for suspicious HID device access: ls -la /dev/hidraw* && stat /dev/hidraw*
  5. Monitor for unusual ioctl calls to HID devices: ausearch -sc ioctl -f /dev/hidraw 2>/dev/null
  6. Verify kernel hardening: cat /proc/cmdline | grep init_on_alloc

Indicators of compromise

  • Unusual access patterns to /dev/hidraw* devices from non-interactive processes
  • Large volumes of HID ioctl calls (HIDIOCGFEATURE) from user-space processes
  • Processes reading from HID devices that are not expected to use HID hardware
  • KASLR bypass indicators followed by privilege escalation

FAQ

Is this exploitable remotely?

No. This requires local access to the system and the ability to interact with HID devices. However, it can be chained with USB-based attacks (malicious USB devices) or used by an attacker who already has local access to leak kernel memory for further exploitation.

Why is a CVSS 5.5 vulnerability in CISA KEV?

Despite the moderate CVSS score, this vulnerability is confirmed to be exploited in targeted attacks as part of exploit chains. Information leaks that defeat KASLR are critical enablers for kernel exploitation, making this a high-value primitive for attackers.

Does CONFIG_INIT_ON_ALLOC_DEFAULT_ON prevent this?

Yes. If the kernel is compiled with CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y (or booted with init_on_alloc=1), heap allocations are zero-initialized, preventing the information leak. Most modern distribution kernels do not enable this by default due to performance impact.

Are containers affected?

Containers share the host kernel, so if the host kernel is vulnerable and the container has access to HID devices (which is uncommon), exploitation is possible. In most container deployments, HID devices are not exposed.

Is this related to other USB/HID CVEs?

The Linux kernel's USB and HID subsystem has had several vulnerabilities. This specific issue is about uninitialized memory, separate from the UVC parser bugs (CVE-2024-53104) or USB audio issues (CVE-2024-53197), though they share the common theme of insufficient input validation in USB device handling.

Related Kernel CVEs

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CVE-2026-64125CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: net: bcmgenet: keep RBUF EEE/PM disabled Setting RBUF_EEE_EN | RBUF_PM_EN in RBUF_ENERGY_CTRL breaks the RX path on GENET hardware once MAC EEE becomes active. RX traffic stops flowing while the link stays up and the usual descriptor/RX error counters remain quiet. In that state the MAC still accepts frames (rbuf_ovflow_cnt keeps climbing) but RBUF no longer forwards them to DMA, so rx_packets is no longer incremented at the netdev level. On some boards the corruption ends up as a paging fault in skb_release_data via bcmgenet_rx_poll on an LPI exit. Reproduced on Pi 4B (BCM2711 + BCM54213PE) and confirmed by Florian Fainelli on an internal Broadcom 4908-family board with the same crash signature. RBUF_PM_EN is not publicly documented. This shows up more often now that phy_support_eee() enables EEE by default, but it also affects older kernels as soon as TX LPI is turned on via ethtool, so it is not specific to recent changes. Always clear RBUF_EEE_EN | RBUF_PM_EN in bcmgenet_eee_enable_set so the bits stay off across resets. UMAC and TBUF setup is left alone so TX-side EEE keeps working.
CVE-2026-64136CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: smb: client: protect tc_count increment in smb2_find_smb_sess_tcon_unlocked() Commit 96c4af418586 ("cifs: Fix locking usage for tcon fields") refactored cifs code to change cifs_tcp_ses_lock for tc_lock around tc_count changes. There was missing lock around tc_count increment inside smb2_find_smb_sess_tcon_unlocked().
CVE-2026-53399CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: nfsd: release layout stid on setlease failure nfs4_alloc_stid() publishes the new stid into cl->cl_stateids via idr_alloc_cyclic() under cl_lock before returning to nfsd4_alloc_layout_stateid(). When nfsd4_layout_setlease() then fails, the error path frees the layout stateid directly with kmem_cache_free() without ever calling idr_remove(), leaving the IDR slot pointing at freed slab memory. Any subsequent IDR walker (states_show, client teardown) dereferences the dangling pointer. The correct teardown for an IDR-published stid is nfs4_put_stid(), which removes the IDR slot under cl_lock, dispatches sc_free (nfsd4_free_layout_stateid) to release ls->ls_file via nfsd4_close_layout(), and drops the nfs4_file reference in its tail. A second issue blocks that switch: nfsd4_free_layout_stateid() unconditionally inspects ls->ls_fence_work via delayed_work_pending() under ls_lock, but INIT_DELAYED_WORK(&ls->ls_fence_work, ...) currently runs only after the setlease call. On the setlease-failure path the destructor would touch an uninitialized delayed_work. nfsd4_alloc_layout_stateid() nfs4_alloc_stid() /* idr_alloc_cyclic under cl_lock */ nfsd4_layout_setlease() /* fails */ nfs4_put_stid() nfsd4_free_layout_stateid() delayed_work_pending(&ls->ls_fence_work) /* needs INIT */ nfsd4_close_layout() /* nfsd_file_put(ls->ls_file) */ put_nfs4_file() Fix by hoisting the ls_fenced / ls_fence_delay / INIT_DELAYED_WORK initialization above the nfsd4_layout_setlease() call, and replace the manual nfsd_file_put + put_nfs4_file + kmem_cache_free cleanup with a single nfs4_put_stid(stp).

References

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