high CVSS 7.8

CVE-2024-36940·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: pinctrl: core: delete incorrect free in pinctrl_enable() The "pctldev" struct is allocated in devm_pinctrl_register_and_init(). It's a devm_ managed pointer that is freed by devm_pinctrl_dev_release(), so freeing it in pinctrl_enable() will lead to a double free. The devm_pinctrl_dev_release() function frees the pindescs and destroys the mutex as well.

Severity
high
Software
Kernel
Fixed in
6.8.10
Published
2024-05-30

Affected versions

From: 6.7

Until: 6.8.10

Fixed in: 6.8.10

How to fix this CVE

Update your Linux kernel to version 6.8.10 or later to resolve a double-free vulnerability in the pinctrl subsystem. This flaw occurs when pinctrl_enable() incorrectly attempts to free device-managed memory that is already tracked by the kernel's devm allocator, potentially causing kernel crashes or memory corruption. Apply the patch immediately through your distribution's kernel update mechanism.

sudo dnf update kernel kernel-devel kernel-headers

Defensia detects this vulnerability

How to check if you are affected

  1. Check kernel version: uname -r — confirm it is 6.8.10 or later
  2. Verify pinctrl module is loaded: lsmod | grep pinctrl — check if vulnerable subsystem is active on your system
  3. Search kernel logs for pinctrl errors: sudo dmesg | grep -i pinctrl — look for double-free warnings or kernel oops messages
  4. Validate patch application: grep -r 'pinctrl_enable' /usr/src/linux-headers-$(uname -r)/ 2>/dev/null | head -5 — inspect source to confirm devm allocation fix is in place

FAQ

What is CVE-2024-36940?

CVE-2024-36940 is a double-free vulnerability in the Linux kernel's pinctrl (pin control) subsystem. The pinctrl_enable() function incorrectly attempts to free device-managed memory that is already automatically freed by the kernel's devm allocator, leading to memory corruption or kernel panic.

Is CVE-2024-36940 being actively exploited?

No, this vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog and no public exploits are available. It requires local kernel code execution capability to trigger.

What versions of Kernel are affected by CVE-2024-36940?

Linux kernel versions 6.7 through 6.8.9 are affected. The vulnerability was fixed in kernel 6.8.10 and later stable releases.

How do I check if my server is vulnerable to CVE-2024-36940?

Run `uname -r` to check your kernel version. If it returns a version between 6.7.x and 6.8.9 (inclusive), your system is vulnerable. Verify the pinctrl module is in use with `lsmod | grep pinctrl`.

Does Defensia detect CVE-2024-36940?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If the Linux kernel is installed on a monitored server running version 6.7–6.8.9, CVE-2024-36940 will appear in your dashboard with remediation steps and patch availability.

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-2022-48716CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: ASoC: codecs: wcd938x: fix incorrect used of portid Mixer controls have the channel id in mixer->reg, which is not same as port id. port id should be derived from chan_info array. So fix this. Without this, its possible that we could corrupt struct wcd938x_sdw_priv by accessing port_map array out of range with channel id instead of port id.

References

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