Vulnerability in Linux

CVE-2025-38552

In the Linux kernel, the following vulnerability has been resolved: mptcp: plug races between subflow fail and subflow creation We have races similar to the one addressed by the previous patch between subflow failing and additional subflow creation. They are just harder to trigger. The solution is similar. Use a separate flag to track the condition 'socket state prevent any additional subflow creation' protected by the fallback lock. The socket fallback makes such flag true, and also receiving or sending an MP_FAIL option. The field 'allow_infinite_fallback' is now always touched under the relevant lock, we can drop the ONCE annotation on write.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.4 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H.

EPSS exploit prediction

EPSS: 0.003 (22.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 22nd percentile — 22.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2025-38552: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.000

Affected products

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-38552?
CVE-2025-38552 is a critical-severity vulnerability in Linux. CVSS score: 9.4/10. Published 2025-08-16.
How severe is CVE-2025-38552?
Critical severity. CVSS v3 base score is 9.4 out of 10.
Is CVE-2025-38552 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.