high CVSS 7.1 EPSS <0.1%

CVE-2024-41935·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to shrink read extent node in batches We use rwlock to protect core structure data of extent tree during its shrink, however, if there is a huge number of extent nodes in extent tree, during shrink of extent tree, it may hold rwlock for a very long time, which may trigger kernel hang issue. This patch fixes to shrink read extent node in batches, so that, critical region of the rwlock can be shrunk to avoid its extreme long time hold.

Severity
high
Software
Kernel
Fixed in
6.12.5
Published

How likely is exploitation

FIRST's Exploit Prediction Scoring System puts the probability of this CVE being exploited in the next 30 days at <0.1% — in the bottom 1% of all published CVEs. EPSS is an independent forecast of exploitation, not a severity rating: it says nothing about how much damage a successful attack does, which is what a CVSS score measures.

Read the two together. CVE-2024-41935 scores 7.1 on CVSS, so a successful attack would be serious — but at <0.1%, almost nobody is currently attempting it. That is a different situation from a flaw under mass exploitation, and it is usually the difference between patching on your next maintenance window and patching tonight.

Affected versions

From: 6.7

Until: 6.12.5

Fixed in: 6.12.5

How to fix this CVE

Update your Linux kernel to version 6.12.5 or later to resolve this rwlock contention issue in the f2fs filesystem. The vulnerability causes the kernel to hold read-write locks for extended periods during extent tree shrinking operations, potentially triggering system hangs. Prioritize this patch if you are running f2fs filesystems, particularly on systems with large extent trees that experience frequent memory pressure events.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Check your current kernel version with: uname -r — compare against the affected range 6.7 to 6.12.4
  2. Verify if f2fs is in use by running: mount | grep f2fs — if no output, this vulnerability does not expose your system
  3. Search system logs for hangs or lockup warnings during high I/O periods: grep -i 'rwlock\|extent\|hang' /var/log/kern.log or journalctl -u kernel | grep -i 'hung task'
  4. Confirm the patch is applied by checking kernel build info: cat /proc/version | grep -o '[0-9]*\.[0-9]*\.[0-9]*' — verify version is 6.12.5 or higher

FAQ

What is CVE-2024-41935?

This vulnerability affects the Linux kernel's f2fs filesystem implementation where the extent tree shrinking routine holds an rwlock (read-write lock) for excessively long periods when processing large numbers of extent nodes, causing potential kernel hangs and system unresponsiveness.

Is CVE-2024-41935 being actively exploited?

No, this vulnerability is not listed in CISA's Known Exploited Vulnerabilities catalog and no public exploits are available. However, it can still cause denial-of-service conditions through normal filesystem operations.

What versions of Kernel are affected by CVE-2024-41935?

Kernel versions 6.7 through 6.12.4 are affected. The fix is available starting from kernel version 6.12.5.

How do I check if my server is vulnerable to CVE-2024-41935?

Run uname -r to check your kernel version and mount | grep f2fs to confirm f2fs usage. If your kernel version is between 6.7 and 6.12.4 and f2fs is mounted, your system is vulnerable.

Does Defensia detect CVE-2024-41935?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If the Linux kernel package is installed on a monitored server, CVE-2024-41935 will appear in your dashboard with remediation steps.

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References

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