high CVSS 7.1 EPSS <0.1%

CVE-2022-49687·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: virtio_net: fix xdp_rxq_info bug after suspend/resume The following sequence currently causes a driver bug warning when using virtio_net: # ip link set eth0 up # echo mem > /sys/power/state (or e.g. # rtcwake -s 10 -m mem) <resume> # ip link set eth0 down Missing register, driver bug WARNING: CPU: 0 PID: 375 at net/core/xdp.c:138 xdp_rxq_info_unreg+0x58/0x60 Call trace: xdp_rxq_info_unreg+0x58/0x60 virtnet_close+0x58/0xac __dev_close_many+0xac/0x140 __dev_change_flags+0xd8/0x210 dev_change_flags+0x24/0x64 do_setlink+0x230/0xdd0 ... This happens because virtnet_freeze() frees the receive_queue completely (including struct xdp_rxq_info) but does not call xdp_rxq_info_unreg(). Similarly, virtnet_restore() sets up the receive_queue again but does not call xdp_rxq_info_reg(). Actually, parts of virtnet_freeze_down() and virtnet_restore_up() are almost identical to virtnet_close() and virtnet_open(): only the calls to xdp_rxq_info_(un)reg() are missing. This means that we can fix this easily and avoid such problems in the future by just calling virtnet_close()/open() from the freeze/restore handlers. Aside from adding the missing xdp_rxq_info calls the only difference is that the refill work is only cancelled if netif_running(). However, this should not make any functional difference since the refill work should only be active if the network interface is actually up.

Severity
high
Software
Kernel
Fixed in
5.18.8
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 10% 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-2022-49687 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: 5.16

Until: 5.18.8

Fixed in: 5.18.8

How to fix this CVE

Update your Linux kernel to version 5.18.8 or later to resolve the xdp_rxq_info lifecycle management issue that occurs during suspend/resume cycles on virtio_net devices. This vulnerability causes kernel warnings and potential system instability when toggling network interfaces after power state transitions. Apply the patch through your distribution's package manager to ensure proper cleanup of XDP receive queue metadata during freeze/restore operations.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Step 1: Check current kernel version with `uname -r` and compare against 5.18.8 — versions 5.16.x through 5.18.7 are vulnerable
  2. Step 2: Verify virtio_net is in use by running `lsmod | grep virtio_net` to confirm the affected driver is loaded
  3. Step 3: Search system logs for the warning pattern with `sudo dmesg | grep -i 'xdp_rxq_info_unreg\|Missing register, driver bug'` to check for exploitation signs
  4. Step 4: After patching, confirm the new kernel is running with `uname -r` and verify it shows version 5.18.8 or later, then test suspend/resume cycle: `echo mem | sudo tee /sys/power/state` followed by `sudo ip link set eth0 down` without observing kernel warnings

FAQ

What is CVE-2022-49687?

This vulnerability affects the Linux kernel's virtio_net driver and causes improper handling of XDP receive queue metadata during system suspend and resume operations. When a network interface is brought down after resuming from sleep, the kernel generates a driver bug warning due to missing xdp_rxq_info registration/unregistration calls.

Is CVE-2022-49687 being actively exploited?

No, this CVE is not listed on the CISA KEV catalog and has no known public exploits. It is primarily a system stability and kernel reliability issue rather than a direct security threat.

What versions of Kernel are affected by CVE-2022-49687?

Linux kernel versions 5.16.0 through 5.18.7 are vulnerable. Kernel 5.18.8 and later versions contain the fix.

How do I check if my server is vulnerable to CVE-2022-49687?

Run `uname -r` to display your kernel version. If it shows a version between 5.16.0 and 5.18.7 and you are using virtio_net (check with `lsmod | grep virtio_net`), your system is vulnerable.

Does Defensia detect CVE-2022-49687?

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-2022-49687 will appear in your dashboard with remediation steps.

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References

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