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Debian LinuxOperating system · Debian

CVE-2024-49924

HIGH · 7.8 CVSS v3.1 Published 2024-10-21
Fix available
A fix is available. Upgrade to 4.19.323 / 5.4.285 or later.
See remediation →
80/100
Remediation priority · High
Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-416

Memory is used after it has been freed, so its contents — now potentially attacker-controlled — drive the program's behaviour. With careful heap grooming this becomes code execution. The fix requires disciplined ownership of memory and often a targeted rework of the object lifecycle.

General guidance for the use after free class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Debian LinuxOperating system
Affected:= 11.0
Linux KernelOperating system
Affected:>= 2.6.27, < 4.19.323>= 4.20, < 5.4.285>= 5.5, < 5.10.227>= 5.11, < 5.15.168>= 5.16, < 6.1.113>= 6.2, < 6.6.55>= 6.7, < 6.10.14>= 6.11, < 6.11.3

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 4.19.323 / 5.4.285 / 5.10.227 or later
Fixed in 4.19.3235.4.2855.10.227
Vendor patch git.kernel.org →
Recommended fix High confidence

Linux kernel >= 4.19.323 (for 4.19.x branch), >= 5.4.285 (for 5.4.x branch), >= 5.10.227 (for 5.10.x branch), or >= 5.15.168 (for 5.15.x branch)

  1. Identify the currently running Linux kernel version using `uname -r`
  2. Determine which version branch your kernel belongs to (4.19.x, 5.4.x, 5.10.x, or 5.15.x)
  3. Upgrade the Linux kernel to a version that includes the fix: for 4.19 branch upgrade to >= 4.19.323, for 5.4 branch upgrade to >= 5.4.285, for 5.10 branch upgrade to >= 5.10.227, for 5.15 branch upgrade to >= 5.15.168
  4. On Debian 11 (Bullseye), update kernel via `apt update && apt upgrade` or by installing a newer kernel package from backports
  5. Reboot the system to load the patched kernel
  6. Verify the fix is applied by checking the kernel version matches or exceeds the fixed release
Caveat Kernel upgrades may require rebuilding third-party kernel modules; ensure compatibility with the new kernel version before production deployment

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $3,200. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2024-49924 in production — separate from our analysis above.

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What this is

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