high CVSS 7.8 EPSS <0.1%

CVE-2024-53173·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: NFSv4.0: Fix a use-after-free problem in the asynchronous open() Yang Erkun reports that when two threads are opening files at the same time, and are forced to abort before a reply is seen, then the call to nfs_release_seqid() in nfs4_opendata_free() can result in a use-after-free of the pointer to the defunct rpc task of the other thread. The fix is to ensure that if the RPC call is aborted before the call to nfs_wait_on_sequence() is complete, then we must call nfs_release_seqid() in nfs4_open_release() before the rpc_task is freed.

Severity
high
Software
Kernel
Fixed in
6.12.2
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% — higher than 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-2024-53173 scores 7.8 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: 6.12

Until: 6.12.2

Fixed in: 6.12.2

How to fix this CVE

Update your Linux kernel to version 6.12.2 or later to resolve a use-after-free vulnerability in NFSv4.0 that can be triggered when concurrent file open operations are aborted prematurely. This race condition affects kernel versions 6.12 through 6.12.1 and requires immediate patching to prevent potential system crashes or privilege escalation on systems using NFS.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Run 'uname -r' to check your current kernel version. Verify if it falls in the range 6.12.0 to 6.12.1.
  2. Check if NFS is mounted or enabled on the system with 'mount | grep nfs' or 'systemctl status nfs-client'.
  3. Review system logs with 'dmesg | tail -100' and 'journalctl -xe' for UAF-related kernel panics, null pointer dereference errors, or RPC task memory corruption messages.
  4. After applying the kernel update, confirm the fix with 'uname -r' and verify the new version is 6.12.2 or higher, then reboot if needed.

FAQ

What is CVE-2024-53173?

CVE-2024-53173 is a use-after-free vulnerability in the Linux kernel's NFSv4.0 implementation that occurs when two threads attempt to open files concurrently and abort before receiving a response, leading to unsafe memory access and potential system instability.

Is CVE-2024-53173 being actively exploited?

No, there is no evidence of active exploitation in the wild, and no public exploits are currently available for this vulnerability.

What versions of Kernel are affected by CVE-2024-53173?

Linux kernel versions 6.12.0, 6.12.1, and 6.12.2 (pre-patch) are affected. The vulnerability is resolved in kernel 6.12.2 and later.

How do I check if my server is vulnerable to CVE-2024-53173?

Run 'uname -r' to display your kernel version. If it shows 6.12.0 or 6.12.1, your system is vulnerable. Additionally, confirm NFS usage with 'mount | grep nfs'.

Does Defensia detect CVE-2024-53173?

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-2024-53173 will appear in your dashboard with remediation steps.

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References

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