high CVSS 7.8 EPSS <0.1%

CVE-2024-43873·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: vhost/vsock: always initialize seqpacket_allow There are two issues around seqpacket_allow: 1. seqpacket_allow is not initialized when socket is created. Thus if features are never set, it will be read uninitialized. 2. if VIRTIO_VSOCK_F_SEQPACKET is set and then cleared, then seqpacket_allow will not be cleared appropriately (existing apps I know about don't usually do this but it's legal and there's no way to be sure no one relies on this). To fix: - initialize seqpacket_allow after allocation - set it unconditionally in set_features

Severity
high
Software
Kernel
Fixed in
6.10.3
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 6% 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-2024-43873 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: 6.7

Until: 6.10.3

Fixed in: 6.10.3

How to fix this CVE

Update your Linux kernel to version 6.10.3 or later to resolve an uninitialized memory state issue in the vhost/vsock driver. This vulnerability affects kernel versions 6.7 through 6.10.2, where the seqpacket_allow field may be read in an uninitialized state or fail to clear properly when VIRTIO_VSOCK_F_SEQPACKET features are toggled. Apply the patch immediately on systems running affected kernel versions, particularly those utilizing vsock virtual sockets for container or VM communication.

sudo dnf update kernel

Defensia detects this vulnerability

How to check if you are affected

  1. Check installed kernel version: uname -r | grep -E '^6\.(7|8|9|10\.[0-2])' and confirm if version falls within 6.7 to 6.10.2 range
  2. Verify vsock driver is in use: lsmod | grep vsock and check for vhost_vsock or virtio_vsock modules loaded
  3. Check dmesg for vsock-related errors: dmesg | grep -i vsock and look for uninitialized variable warnings or feature negotiation failures
  4. Verify patched kernel is running: uname -r should show 6.10.3 or later after reboot following kernel update

FAQ

What is CVE-2024-43873?

CVE-2024-43873 is a memory initialization vulnerability in the Linux kernel's vhost/vsock virtual socket driver where the seqpacket_allow field is not properly initialized at socket creation and may not be cleared when VIRTIO_VSOCK_F_SEQPACKET feature flags are disabled, potentially leading to information disclosure or inconsistent socket behavior.

Is CVE-2024-43873 being actively exploited?

No, CVE-2024-43873 is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog and no public exploits are available as of this writing.

What versions of Kernel are affected by CVE-2024-43873?

Linux kernel versions 6.7 through 6.10.2 are affected; kernel 6.10.3 and later versions contain the fix.

How do I check if my server is vulnerable to CVE-2024-43873?

Run 'uname -r' and check if the kernel version matches 6.7.x, 6.8.x, 6.9.x, or 6.10.0-6.10.2; additionally verify vsock is in use with 'lsmod | grep vsock' to confirm potential exposure.

Does Defensia detect CVE-2024-43873?

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-2024-43873 will appear in your dashboard with remediation steps and version mismatch alerts.

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References

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