CVE-2025-22058

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

udp: Fix memory accounting leak.

Matt Dowling reported a weird UDP memory usage issue.

Under normal operation, the UDP memory usage reported in /proc/net/sockstat

remains close to zero. However, it occasionally spiked to 524,288 pages

and never dropped. Moreover, the value doubled when the application was

terminated. Finally, it caused intermittent packet drops.

We can reproduce the issue with the script below [0]:

1. /proc/net/sockstat reports 0 pages

# cat /proc/net/sockstat | grep UDP:

UDP: inuse 1 mem 0

2. Run the script till the report reaches 524,288

# python3 test.py & sleep 5

# cat /proc/net/sockstat | grep UDP:

UDP: inuse 3 mem 524288 <-- (INT_MAX + 1) >> PAGE_SHIFT

3. Kill the socket and confirm the number never drops

# pkill python3 && sleep 5

# cat /proc/net/sockstat | grep UDP:

UDP: inuse 1 mem 524288

4. (necessary since v6.0) Trigger proto_memory_pcpu

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References