high CVSS 7.8

CVE-2024-27043·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: media: edia: dvbdev: fix a use-after-free In dvb_register_device, *pdvbdev is set equal to dvbdev, which is freed in several error-handling paths. However, *pdvbdev is not set to NULL after dvbdev's deallocation, causing use-after-frees in many places, for example, in the following call chain: budget_register |-> dvb_dmxdev_init |-> dvb_register_device |-> dvb_dmxdev_release |-> dvb_unregister_device |-> dvb_remove_device |-> dvb_device_put |-> kref_put When calling dvb_unregister_device, dmxdev->dvbdev (i.e. *pdvbdev in dvb_register_device) could point to memory that had been freed in dvb_register_device. Thereafter, this pointer is transferred to kref_put and triggering a use-after-free.

Severity
high
Software
Kernel
Fixed in
6.8.2
Published
2024-05-01

Affected versions

From: 6.8

Until: 6.8.2

Fixed in: 6.8.2

How to fix this CVE

Update your Linux kernel to version 6.8.2 or later to resolve this use-after-free vulnerability in the DVB device registration subsystem. The vulnerability occurs when error paths in dvb_register_device fail to null-check device pointers, leading to potential memory access violations during device unregistration. Apply the latest stable kernel patches immediately, particularly if your system uses DVB (Digital Video Broadcasting) hardware or drivers.

sudo dnf upgrade kernel kernel-headers kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Step 1: Check installed kernel version with `uname -r` and verify it is 6.8.2 or later
  2. Step 2: Confirm DVB subsystem is loaded by running `lsmod | grep -i dvb` to identify if media drivers are in use
  3. Step 3: Search system logs for use-after-free warnings with `sudo dmesg | grep -i 'use-after-free\|dvb\|kref'` or check `/var/log/kern.log` for related errors
  4. Step 4: After applying patches, verify the new kernel version with `uname -r` and reboot if necessary to activate the fix

FAQ

What is CVE-2024-27043?

CVE-2024-27043 is a use-after-free vulnerability in the Linux kernel's DVB device management code where error handling paths fail to clear device pointers, allowing subsequent operations to access freed memory and potentially crash the system or execute arbitrary code.

Is CVE-2024-27043 being actively exploited?

No, CVE-2024-27043 is not currently listed as actively exploited by CISA, and no public exploits have been disclosed. However, it remains a high-severity vulnerability that should be patched promptly.

What versions of Kernel are affected by CVE-2024-27043?

Kernel versions 6.8 through 6.8.2 are affected. The vulnerability was resolved in version 6.8.2 and later stable releases.

How do I check if my server is vulnerable to CVE-2024-27043?

Run `uname -r` to display your kernel version; if it shows 6.8.0, 6.8.1, or 6.8.2 (without a higher patch level), your system is vulnerable. Cross-reference against your distribution's security advisories for the exact patched version available.

Does Defensia detect CVE-2024-27043?

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-2024-27043 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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