high CVSS 7.8

CVE-2024-49924·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: fbdev: pxafb: Fix possible use after free in pxafb_task() In the pxafb_probe function, it calls the pxafb_init_fbinfo function, after which &fbi->task is associated with pxafb_task. Moreover, within this pxafb_init_fbinfo function, the pxafb_blank function within the &pxafb_ops struct is capable of scheduling work. If we remove the module which will call pxafb_remove to make cleanup, it will call unregister_framebuffer function which can call do_unregister_framebuffer to free fbi->fb through put_fb_info(fb_info), while the work mentioned above will be used. The sequence of operations that may lead to a UAF bug is as follows: CPU0 CPU1 | pxafb_task pxafb_remove | unregister_framebuffer(info) | do_unregister_framebuffer(fb_info) | put_fb_info(fb_info) | // free fbi->fb | set_ctrlr_state(fbi, state) | __pxafb_lcd_power(fbi, 0) | fbi->lcd_power(on, &fbi->fb.var) | //use fbi->fb Fix it by ensuring that the work is canceled before proceeding with the cleanup in pxafb_remove. Note that only root user can remove the driver at runtime.

Severity: high
Software: Kernel
Fixed in: 6.11.3
Published: 2024-10-21

Affected versions

From: 6.11

Until: 6.11.3

Fixed in: 6.11.3

How to fix this CVE

Update your Linux kernel to version 6.11.3 or later to patch a use-after-free vulnerability in the PXA framebuffer driver. The vulnerability occurs when kernel module removal races with pending framebuffer tasks, potentially allowing memory corruption. Prioritize this update for systems running kernel versions 6.11.0 through 6.11.2, especially those with PXA display hardware or framebuffer drivers loaded.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

Step 1: Check kernel version with `uname -r` — vulnerable if output shows 6.11.0, 6.11.1, or 6.11.2
Step 2: Verify if PXA framebuffer driver is loaded with `lsmod | grep pxafb` or `grep -i pxafb /proc/modules`
Step 3: Search kernel logs for framebuffer-related crashes: `dmesg | grep -iE '(pxafb|framebuffer|use.after.free|UAF)'` or `journalctl -k | grep -iE '(pxafb|use.after.free)'`
Step 4: After patching, verify new kernel version with `uname -r` — should show 6.11.3 or higher

FAQ

What is CVE-2024-49924?

CVE-2024-49924 is a use-after-free vulnerability in the Linux kernel's PXA framebuffer driver where pending work tasks access freed memory structures during module removal, potentially allowing privilege escalation or denial of service.

Is CVE-2024-49924 being actively exploited?

No, CVE-2024-49924 is not listed in the CISA Known Exploited Vulnerabilities catalog and has no publicly available exploits, though exploitation requires root privileges to unload the driver.

What versions of Kernel are affected by CVE-2024-49924?

Linux kernel versions 6.11.0, 6.11.1, and 6.11.2 are vulnerable; the fix is included in kernel 6.11.3 and later stable releases.

How do I check if my server is vulnerable to CVE-2024-49924?

Run `uname -r` and check if the output matches 6.11.0-6.11.2; additionally run `lsmod | grep pxafb` to confirm the vulnerable framebuffer driver is loaded on your system.

Does Defensia detect CVE-2024-49924?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Kernel is installed on a monitored server, CVE-2024-49924 will appear in your dashboard with remediation steps.

Related Kernel CVEs

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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-2024-38541CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: of: module: add buffer overflow check in of_modalias() In of_modalias(), if the buffer happens to be too small even for the 1st snprintf() call, the len parameter will become negative and str parameter (if not NULL initially) will point beyond the buffer's end. Add the buffer overflow check after the 1st snprintf() call and fix such check after the strlen() call (accounting for the terminating NUL char).

References

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