What’s Vulnerable › Vulnerabilities

CVE-2021-47024: vsock/virtio: free queued packets when closing socket

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2024-02-28 · updated 2026-06-17
• Weakness: CWE-401

Description

In the Linux kernel, the following vulnerability has been resolved: vsock/virtio: free queued packets when closing socket As reported by syzbot [1], there is a memory leak while closing the socket. We partially solved this issue with commit ac03046ece2b ("vsock/virtio: free packets during the socket release"), but we forgot to drain the RX queue when the socket is definitely closed by the scheduled work. To avoid future issues, let's use the new virtio_transport_remove_sock() to drain the RX queue before removing the socket from the af_vsock lists calling vsock_remove_sock(). [1] https://syzkaller.appspot.com/bug?extid=24452624fc4c571eedd9

Affected products

• Linux kernel: from 5.2 before 5.10.37; from 5.11 before 5.11.21; from 5.12 before 5.12.4 — fixed in 5.10.37, 5.11.21, 5.12.4

How to fix

Upgrade to a fixed version: Linux kernel 5.10.37, 5.11.21, 5.12.4. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/27691665145e74a45034a9dccf1150cf1894763a
• https://git.kernel.org/stable/c/37c38674ef2f8d7e8629e5d433c37d6c1273d16b
• https://git.kernel.org/stable/c/8432b8114957235f42e070a16118a7f750de9d39
• https://git.kernel.org/stable/c/b605673b523fe33abeafb2136759bcbc9c1e6ebf
• https://git.kernel.org/stable/c/27691665145e74a45034a9dccf1150cf1894763a
• https://git.kernel.org/stable/c/37c38674ef2f8d7e8629e5d433c37d6c1273d16b
• https://git.kernel.org/stable/c/8432b8114957235f42e070a16118a7f750de9d39
• https://git.kernel.org/stable/c/b605673b523fe33abeafb2136759bcbc9c1e6ebf

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