Out-of-bounds Read in Linux

CVE-2025-21815

In the Linux kernel, the following vulnerability has been resolved: mm/compaction: fix UBSAN shift-out-of-bounds warning syzkaller reported a UBSAN shift-out-of-bounds warning of (1UL << order) in isolate_freepages_block(). The bogus compound_order can be any value because it is union with flags. Add back the MAX_PAGE_ORDER check to fix the warning.

Vulnerability class: Buffer Overflow

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H.

EPSS exploit prediction

EPSS: 0.002 (8.1th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 8th percentile — 8.1% 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-2025-21815: held from 0.002 to 0.002.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2025-21815?
CVE-2025-21815 is a high-severity vulnerability in Linux, classified under Out-of-bounds Read. CVSS score: 7.1/10. Published 2025-02-27.
How severe is CVE-2025-21815?
High severity. CVSS v3 base score is 7.1 out of 10.