Buffer overflow in Linux

CVE-2025-39727

In the Linux kernel, the following vulnerability has been resolved: mm: swap: fix potential buffer overflow in setup_clusters() In setup_swap_map(), we only ensure badpages are in range (0, last_page]. As maxpages might be < last_page, setup_clusters() will encounter a buffer overflow when a badpage is >= maxpages. Only call inc_cluster_info_page() for badpage which is < maxpages to fix the issue.

Vulnerability class: Buffer Overflow

EPSS: 0.002 (5.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-39727?
CVE-2025-39727 is a high-severity vulnerability in Linux, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 7.8/10. Published 2025-09-07.
How severe is CVE-2025-39727?
High severity. CVSS v3 base score is 7.8 out of 10.
Is CVE-2025-39727 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.