Use After Free in Linux

CVE-2025-21671

In the Linux kernel, the following vulnerability has been resolved: zram: fix potential UAF of zram table If zram_meta_alloc failed early, it frees allocated zram->table without setting it NULL. Which will potentially cause zram_meta_free to access the table if user reset an failed and uninitialized device.

Vulnerability class: Use-After-Free

Published · last modified .

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.

EPSS exploit prediction

EPSS: 0.002 (10.9th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 11th percentile — 10.9% 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-2025-21671: held from 0.002 to 0.002.

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

Affected products

  • Linux — versions ac3b5366b9b7c9d97b606532ceab43d2329a22f3, 0b5b0b65561b34e6e360de317e4bcd031bfabf42, 6fb92e9a52e3feae309a213950f21dfcd1eb0b40
  • Linux Kernel

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-21671?
CVE-2025-21671 is a high-severity vulnerability in Linux, classified under Use After Free. CVSS score: 7.8/10. Published 2025-01-31.
How severe is CVE-2025-21671?
High severity. CVSS v3 base score is 7.8 out of 10.
Is CVE-2025-21671 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.