high CVSS 7.8

CVE-2024-27000·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: serial: mxs-auart: add spinlock around changing cts state The uart_handle_cts_change() function in serial_core expects the caller to hold uport->lock. For example, I have seen the below kernel splat, when the Bluetooth driver is loaded on an i.MX28 board. [ 85.119255] ------------[ cut here ]------------ [ 85.124413] WARNING: CPU: 0 PID: 27 at /drivers/tty/serial/serial_core.c:3453 uart_handle_cts_change+0xb4/0xec [ 85.134694] Modules linked in: hci_uart bluetooth ecdh_generic ecc wlcore_sdio configfs [ 85.143314] CPU: 0 PID: 27 Comm: kworker/u3:0 Not tainted 6.6.3-00021-gd62a2f068f92 #1 [ 85.151396] Hardware name: Freescale MXS (Device Tree) [ 85.156679] Workqueue: hci0 hci_power_on [bluetooth] (...) [ 85.191765] uart_handle_cts_change from mxs_auart_irq_handle+0x380/0x3f4 [ 85.198787] mxs_auart_irq_handle from __handle_irq_event_percpu+0x88/0x210 (...)

Severity
high
Software
Kernel
Fixed in
6.8.8
Published
2024-05-01

Affected versions

From: 6.7

Until: 6.8.8

Fixed in: 6.8.8

How to fix this CVE

Update your Linux kernel to version 6.8.8 or later to resolve a critical race condition in the MXS UART driver where CTS (Clear to Send) state changes were not properly protected by spinlocks. This vulnerability can cause kernel warnings and potential system instability when Bluetooth or other drivers interact with serial ports. Apply the kernel update immediately through your distribution's package manager.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Step 1: Check your current kernel version by running `uname -r` and compare against the affected range (6.7.x to 6.8.7)
  2. Step 2: Verify if MXS UART driver is loaded by running `lsmod | grep mxs_auart` or checking device tree for mxs-auart compatible nodes in `/proc/device-tree`
  3. Step 3: Search system logs for the specific warning pattern using `sudo journalctl -b | grep -i 'uart_handle_cts_change\|WARNING.*serial_core.c:3453'`
  4. Step 4: Confirm the fix by updating to kernel 6.8.8+ and verifying with `uname -r`, then reboot and check for absence of CTS-related kernel warnings in `sudo journalctl -b`

FAQ

What is CVE-2024-27000?

CVE-2024-27000 is a race condition in the Linux kernel's MXS UART serial driver where the CTS (Clear to Send) state change handler was called without proper spinlock protection. This violation of the serial_core API contract can trigger kernel warnings and potential data corruption when Bluetooth or other drivers interact with affected serial ports.

Is CVE-2024-27000 being actively exploited?

No, there are no known active exploits or public exploit code for CVE-2024-27000. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

What versions of Kernel are affected by CVE-2024-27000?

Kernel versions 6.7.x through 6.8.7 are affected. The vulnerability is resolved in kernel 6.8.8 and later.

How do I check if my server is vulnerable to CVE-2024-27000?

Run `uname -r` to get your kernel version; if it falls between 6.7.0 and 6.8.7, you are vulnerable. Additionally, check if the MXS UART driver is in use with `lsmod | grep mxs_auart` on ARM-based systems like i.MX28.

Does Defensia detect CVE-2024-27000?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If the Linux kernel is installed on a monitored server, CVE-2024-27000 will appear in your dashboard with remediation steps.

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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