medium CVSS 5.5 Actively exploited

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
2024-11-19

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

CVE-2024-42256CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: cifs: Fix server re-repick on subrequest retry When a subrequest is marked for needing retry, netfs will call cifs_prepare_write() which will make cifs repick the server for the op before renegotiating credits; it then calls cifs_issue_write() which invokes smb2_async_writev() - which re-repicks the server. If a different server is then selected, this causes the increment of server->in_flight to happen against one record and the decrement to happen against another, leading to misaccounting. Fix this by just removing the repick code in smb2_async_writev(). As this is only called from netfslib-driven code, cifs_prepare_write() should always have been called first, and so server should never be NULL and the preparatory step is repeated in the event that we do a retry. The problem manifests as a warning looking something like: WARNING: CPU: 4 PID: 72896 at fs/smb/client/smb2ops.c:97 smb2_add_credits+0x3f0/0x9e0 [cifs] ... RIP: 0010:smb2_add_credits+0x3f0/0x9e0 [cifs] ... smb2_writev_callback+0x334/0x560 [cifs] cifs_demultiplex_thread+0x77a/0x11b0 [cifs] kthread+0x187/0x1d0 ret_from_fork+0x34/0x60 ret_from_fork_asm+0x1a/0x30 Which may be triggered by a number of different xfstests running against an Azure server in multichannel mode. generic/249 seems the most repeatable, but generic/215, generic/249 and generic/308 may also show it.
CVE-2024-36031CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: keys: Fix overwrite of key expiration on instantiation The expiry time of a key is unconditionally overwritten during instantiation, defaulting to turn it permanent. This causes a problem for DNS resolution as the expiration set by user-space is overwritten to TIME64_MAX, disabling further DNS updates. Fix this by restoring the condition that key_set_expiry is only called when the pre-parser sets a specific expiry.
CVE-2024-38612CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: ipv6: sr: fix invalid unregister error path The error path of seg6_init() is wrong in case CONFIG_IPV6_SEG6_LWTUNNEL is not defined. In that case if seg6_hmac_init() fails, the genl_unregister_family() isn't called. This issue exist since commit 46738b1317e1 ("ipv6: sr: add option to control lwtunnel support"), and commit 5559cea2d5aa ("ipv6: sr: fix possible use-after-free and null-ptr-deref") replaced unregister_pernet_subsys() with genl_unregister_family() in this error path.
CVE-2024-38623CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: Use variable length array instead of fixed size Should fix smatch warning: ntfs_set_label() error: __builtin_memcpy() 'uni->name' too small (20 vs 256)
CVE-2021-47548CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: ethernet: hisilicon: hns: hns_dsaf_misc: fix a possible array overflow in hns_dsaf_ge_srst_by_port() The if statement: if (port >= DSAF_GE_NUM) return; limits the value of port less than DSAF_GE_NUM (i.e., 8). However, if the value of port is 6 or 7, an array overflow could occur: port_rst_off = dsaf_dev->mac_cb[port]->port_rst_off; because the length of dsaf_dev->mac_cb is DSAF_MAX_PORT_NUM (i.e., 6). To fix this possible array overflow, we first check port and if it is greater than or equal to DSAF_MAX_PORT_NUM, the function returns.

References

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